Reuse compositions only when content key matching

This change declares the content type in the lazy grid so that it only
reuses compositions when the content types are identical.

Bug: 312052098
Bug: 317269504
Fix: 317269504
Test: add 10 widgets in the grid and ensure compositions are reused
correctly
Test: start/pause/unpause smartspace timers and ensure remote views are
recomposed as the key changes
Flag: ACONFIG com.android.systemui.communal_hub DEVELOPMENT

Change-Id: I4e347285916cfec09a9c2a266d715231ac10bafb