Fix disabled state for non-resizeable app pairs

This CL makes it so that app pair creation includes updating some flags on the newly created WorkspaceItemInfos -- specifically the FLAG_NON_RESIZEABLE flag. Previously, flag updating only happened upon launcher restart or package change, which meant that newly created app pairs were missing some flags.

This caused App+Camera pairs to not have the FLAG_NON_RESIZEABLE flag immediately on app pair creation, which affected the disabled state.

Fixes: 323088270
Flag: ACONFIG com.android.wm.shell.enable_app_pairs TRUNKFOOD
Test: Manual
Change-Id: I96c6ec3723bec2ddaa0af625890b983faf2fe2c7