fix: adapt action mode bar to landscape insets

[himu-gupta]

Summary

• Make the contextual multi-selection action bar consume landscape system bar and display cutout insets horizontally.
• Keep the action icons visible by avoiding top inset padding on the AppCompat action mode content.
• Add an unreleased changelog entry.

Fixes #4892

Verification

• JAVA_HOME="/Applications/Android Studio.app/Contents/jbr/Contents/Home" ANDROID_HOME="/Users/himu/Library/Android/sdk" ./gradlew --no-daemon --console=plain :owncloudApp:compileOriginalDebugKotlin
• JAVA_HOME="/Applications/Android Studio.app/Contents/jbr/Contents/Home" ANDROID_HOME="/Users/himu/Library/Android/sdk" ./gradlew --no-daemon --console=plain :owncloudApp:assembleOriginalDebug
• git diff --check

[CLAassistant]

All committers have signed the CLA.

[joragua]

Hi @himu-gupta! Thanks for opening this PR! 🍻

I've checked your code and it does not seem to work as expected because all the icons in the action bar are hidden, and the system bar does not span the full width of the screen. Is the PR still in progress? 🤔 If not, I think this is not a valid solution. Let us know if you have any doubts and we will be happy to help you!

NOTE: Do not forget to use conventional commits for the message. Commits must be GPG/PGP signed, and it'd be great if each commit include a Signed-off-by line. Also, I'd separate the calens into a different commit with the message: chore: add calens file

[joragua]

Just two details before the CR @himu-gupta! 😄

Would it be possible to adjust the content of the action bar in order to prevent overlap between navigation buttons and the buttons from the bar. Also, would it be possible to extend the black system bar across the entire width of the device screen? 🤔 Thanks!