[Autofill Assistant] Fixed recently introduced crash on startup if onboarding screen is shown.

This relates to http://crrev/c/1340940 , where the ID of the bottombar was changed in the layout, but not in code.

This merge request was approved here: https://bugs.chromium.org/p/chromium/issues/detail?id=911035

Bug: 806868
Change-Id: I5869625714d9a747f7468bba3e403db5550c1b3c
Reviewed-on: https://chromium-review.googlesource.com/c/1356544
Reviewed-by: Mathias Carlen <[email protected]>
Commit-Queue: Clemens Arbesser <[email protected]>
Cr-Original-Commit-Position: refs/heads/master@{#612645}(cherry picked from commit 0c26d40)
Reviewed-on: https://chromium-review.googlesource.com/c/1365615
Reviewed-by: Stephane Zermatten <[email protected]>
Cr-Commit-Position: refs/branch-heads/3626@{#109}
Cr-Branched-From: d897fb1-refs/heads/master@{#612437}

Author: Clemens Arbesser

chrome/android/java/src/org/chromium/chrome/browser/autofill_assistant/AutofillAssistantUiDelegate.java

@@ -256,7 +256,7 @@ public AutofillAssistantUiDelegate(ChromeActivity activity, Client client) {
                                  .findViewById(R.id.autofill_assistant);
         // TODO(crbug.com/806868): Set hint text on overlay.
         mTouchEventFilter = (TouchEventFilter) mFullContainer.findViewById(R.id.touch_event_filter);
-        mBottomBar = mFullContainer.findViewById(R.id.bottombar);
+        mBottomBar = mFullContainer.findViewById(R.id.autofill_assistant_bottombar);
         mBottomBarBehavior = BottomSheetBehavior.from(mBottomBar);
         mBottomBar.findViewById(R.id.close_button)
                 .setOnClickListener(unusedView -> mClient.onDismiss());