Add a custom rightClick Espresso ViewAction

Espresso's default click() doesn't emulate a right click well enough for
us. In DocsUI code (e.g. roots list) we listen for Generic Motion events
which only trigger on ACTION_BUTTON_PRESS and since Espresso doesn't
send these events, our tests cannot perform a right click with out a
custom ViewAction. See b/436682861 for more details.

Bug: 436118913
Flag: EXEMPT updating tests
Test: updating tests
Change-Id: Id8effa26851769bba8a591fb188f61fa346c8b39