[Autofill Assistant] Fix crash on Android 4 and 4-

Bug: 912701
Change-Id: I57efa7240173559172b7ccb370a8c18a8cfc6eae
Reviewed-on: https://chromium-review.googlesource.com/c/1366696Reviewed-by: Mathias Carlen <mcarlen@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Commit-Queue: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614722}

chrome/android/java/res_autofill_assistant/layout/autofill_assistant_sheet.xml

@@ -77,7 +77,7 @@
                     android:layout_width="24dp"
                     android:layout_height="24dp"
                     android:layout_marginEnd="12dp"
-                    android:src="@drawable/ic_bug_report_24dp"
+                    app:srcCompat="@drawable/ic_bug_report_24dp"
                     android:tint="@color/light_icon_color"
                     android:background="?attr/selectableItemBackground"
                     android:contentDescription="@string/menu_send_feedback" />