test: device and theme screenshot properties

[BrayanDSO]

global properties to run tests with a tablet frame and/or dark theme

It also sets the MediumPhone qualifier by default, so tests like AllActivitiesScreenshotTest don't need to set it manually

add -Ptheme=dark to use dark theme and -Pdevice=tablet to use a tablet frame

How Has This Been Tested?

./gradlew :AnkiDroid:recordRoborazziPlayDebug -Pscreenshot -Ptheme=dark

./gradlew :AnkiDroid:recordRoborazziPlayDebug -Pscreenshot -Pdevice=tablet

./gradlew :AnkiDroid:recordRoborazziPlayDebug -Pscreenshot -Ptheme=dark -Pdevice=tablet

Checklist

Please, go through these checks before submitting the PR.

• You have a descriptive commit message with a short title (first line, max 50 chars).
• You have commented your code, particularly in hard-to-understand areas
• You have performed a self-review of your own code
• UI changes: include screenshots of all affected screens (in particular showing any new or changed strings)
• UI Changes: You have tested your change using the Google Accessibility Scanner

[david-allison]

LGTM

[criticalAY]

Thankyou!