add workflow_dispatch to other workflow files (#39491)

* add workflow_dispatch to other workflow files

* removed unnecessary workflow changes

Author: derrickaw

.github/workflows/python_dependency_tests.yml

@@ -1,6 +1,7 @@
 name: Python Dependency Tests
 
 on:
+  workflow_dispatch:
   schedule:
     - cron: '10 2 * * *'
   pull_request:

.github/workflows/tour_of_beam_backend_integration.yml

@@ -20,6 +20,7 @@
 name: Tour of Beam Go integration tests
 
 on:
+  workflow_dispatch:
   push:
     branches: ['master', 'release-*']
     tags: 'v*'