Remove WindowConfiguration.setBounds and getBounds annotations

Kotlin can't treat getBounds and setBounds as a paired getter and setter
for an implicit property if getBounds returns @NonNull but setBounds
takes a @Nullable.  Partially revert ag/24341624 by removing the
annotations for now to fix errors from existing kotlin property usage.

Bug: 294110802
Bug: 297672475
Test: builds
Change-Id: Id476474be82cbb8d581c6389723bfde0cedc0e28