Adds onInvocationProgress method to AssistManager.

This will allow Assistant invoction methods such as squeeze to show the
new assistant animations.

Test: Tested locally
BUG:123661896
Change-Id: I6b5cb3e55df3ff109fea1cfcce6d3161f8685401

packages/SystemUI/src/com/android/systemui/assist/AssistManager.java

@@ -204,6 +204,11 @@ public class AssistManager implements ConfigurationChangedReceiver {
         return false;
     }
 
+    /** Called when the user is performing an assistant invocation action (e.g. Active Edge) */
+    public void onInvocationProgress(int type, float progress) {
+        // intentional no-op, vendor's AssistManager implementation should override if needed.
+    }
+
     public void hideAssist() {
         mAssistUtils.hideCurrentSession();
     }