ci fix (#598)

.github/workflows/android_ut.yml

@@ -1,6 +1,6 @@
 name: Android Unit Tests
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   test:

.github/workflows/flutter_ut.yml

@@ -1,6 +1,6 @@
 name: Flutter Unit Tests
 
-on: [push]
+on: [push, pull_request]
 
 jobs:
   test: