Add TaskbarModeSwitchRule to test both transient/persistent taskbar.

- Lays the foundation for transient taskbar tests.
- Does not add flags that would add ACTION_OUTSIDE in tests.
  We can address testing this functionality in a separate CL

Bug: 257549303
Test: TaplTestsTaskbar
Change-Id: I44acc5e589b959e6d4bc93fdc369e503c54e7d87
diff --git a/quickstep/Android.bp b/quickstep/Android.bp
index 7292c44..f5a8253 100644
--- a/quickstep/Android.bp
+++ b/quickstep/Android.bp
@@ -38,6 +38,7 @@
     name: "launcher3-quickstep-oop-tests-src",
     path: "tests",
     srcs: [
+        "tests/src/com/android/quickstep/TaskbarModeSwitchRule.java",
         "tests/src/com/android/quickstep/NavigationModeSwitchRule.java",
         "tests/src/com/android/quickstep/AbstractQuickStepTest.java",
         "tests/src/com/android/quickstep/TaplTestsQuickstep.java",