Hide bubble bar stash handle on the keyboard open.

Added SYSUI_STATE_IME_VISIBLE flag to MASK_HIDE_HANDLE_VIEW to hide the
bubble bar stash handle view. Also update alpha to 1 for the stash
handle view when visibility is updated to VISIBLE.

Fixes: 403363673
Flag: com.android.wm.shell.enable_bubble_bar
Test: Manual. Have stashed bubble bar and multiple system languages.
Go to settings (or ane other apps that has input fields). Click on
search to trigger keyboard pop up. Observe that stash handle is hidden.
Collapse the keyboard and observe that stash handle is shown again.

Change-Id: I5c8518cf02cc784243f9f55a95022279b2608760

quickstep/src/com/android/launcher3/taskbar/bubbles/BubbleStashedHandleViewController.java

@@ -226,6 +226,7 @@ public class BubbleStashedHandleViewController {
     private void updateVisibilityForStateChange() {
         if (!mHiddenForSysui && !mHiddenForHomeButtonDisabled && !mHiddenForNoBubbles) {
             mStashedHandleView.setVisibility(VISIBLE);
+            mStashedHandleView.setAlpha(1);
         } else {
             mStashedHandleView.setVisibility(INVISIBLE);
             mStashedHandleView.setAlpha(0);