Add API for sharesheet text album hint

An integer extra for ACTION_CHOOSER intents that can tell sharesheets
that display a headline to describe the text being shared as an album
(with potential to add other types in future releases).

Test: CTS Verifier
Bug: 323380224

Change-Id: Ia758c28dcdde13c2a0f67ec00cc7f7c9bf99baa3