Left align toolbar popup when larger than viewport

If the popup is wider than the viewport, the clamp becomes invalid since
the minimum bound will be greater than the maximum bound. In this case,
the best that can be done is aligning the popup to the leftmost location.

Bug: 380683878
Test: manual
Flag: NONE bugfix
Change-Id: I277376b40de8ad17c006b82f2160a665ccdc38a2