Bump Python version from 3.7 to 3.11 in GitHub Actions workflows (#14301)

.github/workflows/firestore-nightly.yml

@@ -71,7 +71,7 @@ jobs:
 
     - uses: actions/setup-python@v5
       with:
-        python-version: '3.7'
+        python-version: '3.11'
 
     - name: Install Secret GoogleService-Info.plist
       run: scripts/decrypt_gha_secret.sh scripts/gha-encrypted/firestore-nightly.plist.gpg \

.github/workflows/firestore.yml

@@ -15,6 +15,7 @@
 name: firestore
 
 on:
+  workflow_dispatch:
   pull_request:
   schedule:
     # Run every day at 12am (PST) - cron uses UTC times
@@ -311,7 +312,7 @@ jobs:
 
     - uses: actions/setup-python@v5
       with:
-        python-version: '3.7'
+        python-version: '3.11'
 
     - name: Setup build
       run:  scripts/install_prereqs.sh Firestore ${{ runner.os }} cmake