fix: Band-aid fix to prevent front history crashes

Author: atlas-oc

lib/octocon/fronts.ex

@@ -84,6 +84,7 @@ defmodule Octocon.Fronts do
       )
       |> Repo.all_regional({:user, system_identity})
       |> Enum.sort_by(& &1.time_start, {:desc, DateTime})
+      |> Enum.filter(fn front -> front.alter_id != nil end)
       |> Enum.map(&CurrentFront.to_front/1)
 
     alters =
@@ -223,7 +224,7 @@ defmodule Octocon.Fronts do
          (Repo.all_regional(q2, {:user, system_identity}) |> Enum.map(&FrontByEndTime.to_front/1)) ++
          (Repo.all_regional(q3, {:user, system_identity}) |> Enum.map(&FrontByTime.to_front/1)))
       |> Enum.uniq_by(& &1.id)
-      |> Enum.filter(fn front -> front.time_end != nil end)
+      |> Enum.filter(fn front -> front.time_end != nil && front.alter_id != nil end)
       |> Enum.sort_by(& &1.time_start, {:desc, DateTime})
 
     results
@@ -257,6 +258,7 @@ defmodule Octocon.Fronts do
          (Repo.all_regional(q2, {:user, system_identity})
           |> Enum.each(&FrontByEndTime.to_front/1)))
       |> Enum.uniq_by(& &1.id)
+      |> Enum.filter(fn front -> front.alter_id != nil end)
       |> Enum.sort_by(& &1.time_start, {:desc, DateTime})
 
     results