Fixes issue where the notification menu was not visible after RTL changes

Fixes issue where the notification menu was not visible after RTL changes

- Altered how the menu location is set so that it doesn't depend on RTL
  state
- Also fixes an issue where if you change from landscape to portrait or
  vice versa then the menu wouldn't be visible because the placement is
  based on the width of the notification which changes based on orientation

Test: (1) have notifications and show the menu, toggle the RTL state,
          show the menu, note that it is visible
      (2) have notifications and show the menu, rotate the device, note
          that the menu is still visible
Fixes: 36874498
Change-Id: I3a3b688f2b301f5ac0446a55b668db79c323a95c