Reset pip actions when pip disappears

The Pip menu shows  some default actions (Fullscreen, Close and Move)
and it can also show custom actions from the app or media actions. These
custom actions are Pip-session dependent and should be cleared when the
Pip is finished.

This CL adds a reset() function to the TvPipActionsProvider, which
clears the state for custom actions (both app-defined and media) and any
custom close actions. We reset the TvPipActionsProvider when the pip
disappears in TvPipController

Bug: 289887991
Test: atest TvPipActionProviderTest
Change-Id: I35c1e548d5879a75f147022259db04b3f7a027ea