Fixes the string for the A11yNode action of editing the FAB.

Minor unflagged UX fix, but the feature itself is flagged using `com.android.systemui.floating_menu_drag_to_edit`.

Bug: n/a
Test: Use TalkBack to view the FAB's a11ynode actions.
      Observe correct action name "Edit" instead of "Remove".
Change-Id: I09a3cddb3b2c4e55273c6f75c1d22ef195d9b1e0