fix: Update Shoot rolling upgrades guide in light of new Monitoring tab

When bringing Shoot details into view, we now have a new tab
labeled "Monitoring". We update all relevant screenshots with
newer versions that have this new tab. We also augment the
prose a bit, due to a new screenshot.

Author: colder-is-better

docs/howto/kubernetes/gardener/assets/rollupgr-01.png

@@ -18,20 +18,24 @@ In the central pane, you will see all your {{k8s_management_service}} clusters,
 If a Kubernetes upgrade is available for a shoot cluster, in the *Version* column, you will notice a blue :fontawesome-solid-circle-arrow-up: icon together with the current Kubernetes version.
 Additionally, if there is a new machine image version for the cluster nodes, then in the *Worker Groups* column, you will also notice a blue :fontawesome-solid-circle-arrow-up: icon --- but no version number.
 
-![Garden Linux and Kubernetes upgrades available](assets/rollupgr-01.png)
+![Garden Linux and Kubernetes upgrades available](assets/shoot-rollupgr-01.png)
 
 To get more information about the current machine image, click on the cluster row to bring its details into full view, then select the *Worker Groups* tab.
 There, you will see the version of the current machine image.
 To start the upgrade process, click any of the two :fontawesome-solid-arrow-up: icons.
 
-![About to start Garden Linux upgrade](assets/rollupgr-02.png)
+![About to start Garden Linux upgrade](assets/shoot-rollupgr-02.png)
 
 The upgrade process starts immediately and takes some time to complete.
+The animated icon at the left-hand side of the cluster row marks the progress.
+
+![Garden Linux upgrade in progress](assets/shoot-rollupgr-03.png)
+
 A little before and after it is done, there is no icon in the *Worker Groups* column, and the new image version is displayed in the
 *Image* row of the *Worker Groups* tab.
 Since we have not upgraded Kubernetes yet, an icon is still in the *Version* column.
 
-![Garden Linux upgraded](assets/rollupgr-03.png)
+![Garden Linux upgraded](assets/shoot-rollupgr-04.png)
 
 ## Upgrading Kubernetes
 
@@ -40,13 +44,13 @@ In the pop-up menu that appears, there is an option named *Kubernetes Patch Avai
 That one is not always there, and when it is, it acts as yet another indicator of an available Kubernetes upgrade.
 Please select the option by clicking on it.
 
-![Kubernetes patch available](assets/rollupgr-04.png)
+![Kubernetes patch available](assets/shoot-rollupgr-05.png)
 
 A new pop-up window named *Upgrade Kubernetes Version for: <cluster_name>* appears.
 From the *Version* drop-down menu, you may select the new Kubernetes version you want your cluster to upgrade to.
 When ready, click the blue *Upgrade* button.
 
-![About to start a Kubernetes upgrade](assets/rollupgr-05.png)
+![About to start a Kubernetes upgrade](assets/shoot-rollupgr-06.png)
 
 You will realize that the upgrade doesn't start right away.
 Instead, you are informed that the cluster is indeed ready for it, but there are some notes you might want to read up on *before* the actual process begins.
@@ -55,26 +59,26 @@ The gist of the notes differs depending on whether you're upgrading a shoot with
     In summary, the notes inform you that any existing static kubeconfig will stop working after the upgrade to Kubernetes 1.27, and you will not be able to create a new static kubeconfig.
     You will, however, be able to create [a new certificate-based kubeconfig](kubectl.md).
 
-    ![Upgrade notes are available](assets/rollupgr-06-01.png)
+    ![Upgrade notes are available](assets/shoot-rollupgr-07-26-01.png)
 
     To disable support for static kubeconfigs for the existing cluster and thus prepare the shoot for the upgrade, click the blue button labeled *Prepare cluster upgrade*.
     Another pop-up window appears, indicating that the preparation is underway.
     Keep in mind that this might take up to ten minutes to complete.
 
-    ![Upgrade notes are available](assets/rollupgr-06-02.png)
+    ![Upgrade notes are available](assets/shoot-rollupgr-07-26-02.png)
 
     When the shoot is ready for the upgrade, yet another window appears.
     It lets you know that the shoot is now ready for the upgrade, reminds you that any existing static kubeconfig will not work after the upgrade is complete, and points out that you will not be able to create a new static kubeconfig.
 
-    ![Upgrade notes are available](assets/rollupgr-06-03.png)
+    ![Upgrade notes are available](assets/shoot-rollupgr-07-26-03.png)
 === "Shoot with Kubernetes 1.27 or higher"
     The notes link to the official Kubernetes changelog of the version you are about to upgrade to.
     You may want to copy that link, paste it into a new browser window or tab, and take the time to read the changelog.
 
-    ![Upgrade notes are available](assets/rollupgr-06.png)
+    ![Upgrade notes are available](assets/shoot-rollupgr-07-27-01.png)
 
 Click the *Upgrade* button --- which is now green --- to start the upgrade process.
 After some minutes, the upgrade will be over.
 The new Kubernetes version will be visible in the *Version* column of the cluster row.
 
-![Kubernetes successfully upgraded](assets/rollupgr-07.png)
+![Kubernetes successfully upgraded](assets/shoot-rollupgr-08.png)