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

This reverts commit ae61f7118a [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

core/java/android/view/inputmethod/InputMethodManagerInternal.java

@@ -30,11 +30,6 @@ public interface InputMethodManagerInternal {
      */
     void setInteractive(boolean interactive);
 
-    /**
-     * Called by the window manager to let the input method manager rotate the input method.
-     */
-    void switchInputMethod(boolean forwardDirection);
-
     /**
      * Hides the current input method, if visible.
      */