Use uiContext when trying to get WindowManager or UI related work

There is a silent error log when trying to getWindowManager with
a11yService as the context. Creating a WindowContext before getting the
WindowManager clears out the error log

Bug: 268743197
Test: manually. Turn on/off a11y menu, rotate the screen, clicking on
the menu item all works
Test: atest AccessibilityMenuServiceTests
Flag: EXEMPT low risk bugfix

Change-Id: I0f5f5df85f766f8dc14bd1bc1a534a1eac245faf