Revert "Rotate IMEs (subtypes) by Meta+Space."

This reverts commit ae61f711 [1].

Reason for revert: to deprecate Meta-Space short cut.

 [1]: I4005692215edfcf8bed3e86b1e07000148f986f5

Bug: 79150878
Test: Manually tested as follows.
  1. make -j SoftKeyboard
  2. adb install -r $OUT/system/app/SoftKeyboard/SoftKeyboard.apk
  3. adb shell ime enable com.example.android.softkeyboard/.SoftKeyboard
  4. Connect a hardware keyboard
  5. adb shell settings get secure default_input_method
  6. Hit Meta+Space on the hardware keyboard.
  7. adb shell settings get secure default_input_method
  8. Make sure that the results of step 5 and step 7 are the same.
Change-Id: I5ed0feb5a6d7171564d358644b04ee2a43e4d6b3