[SB][Screen Chips] If sharing a single app, show app name in stop dialog

This CL updates the share-to-app and cast-to-other-device dialogs to
show "You will stop sharing [app name]" if you chose to share just a
single app at the beginning. We need to do this for screen recording
too, but that's more complicated because RecordingController doesn't
have this information yet, so that'll come in another CL.

Bug: 332662551
Flag: com.android.systemui.status_bar_screen_sharing_chips
Test: Start a share-to-app session with a specific app -> click chip ->
verify dialog says "You will stop sharing [app name]", with [app name]
in bold
Test: Start a cast-to-other-device session with a specific app -> click
chip -> verify dialog says "You will stop casting [app name]", with [app
name] in bold
Test: atest MediaProjectionChipInteractorTest
Test: atest EndCastToOtherDeviceDialogDelegateTest
EndShareToAppDialogDelegateTest EndMediaProjectionDialogHelperTest

Change-Id: Ia4aa6132b342127b4b9202ecd40d561c0fb882c2