Remove updateImeParent in RecentsAnimationController

As we added this workaround logic in CL[1] to updateImeParent
for fixing the IME container somehow failed to attach to app task
while swiping the app task after rotating the screen.

Since CL[2] has improved to invoke updateImeControlTarget when
windowConfiguration changed.

As the result, we can get rid of this logic in
RecentsAnimationController and remove it.

[1]: Ia6722e1cbccd7adc8aed1828265f6fa4df78df63
[2]: If5accb22340335c951b37fa29eb8c308179bf645

Bug: 184020899
Test: manual
Change-Id: I735361fc56cee899f874a7cf08c15e526ef1133f

services/core/java/com/android/server/wm/RecentsAnimationController.java

@@ -291,12 +291,6 @@ public class RecentsAnimationController implements DeathRecipient {
                         }
                     }
                     if (!behindSystemBars) {
-                        // Make sure to update the correct IME parent in case that the IME parent
-                        // may be computed as display layer when re-layout window happens during
-                        // rotation but there is intermediate state that the bounds of task and
-                        // the IME target's activity is not the same during rotating.
-                        mDisplayContent.updateImeParent();
-
                         // Hiding IME if IME window is not attached to app.
                         // Since some windowing mode is not proper to snapshot Task with IME window
                         // while the app transitioning to the next task (e.g. split-screen mode)