fix(ci): prevent parallel UI tests from competing for same email inbox

- Change concurrency group from per-platform to shared 'ui-tests-email-inbox'
- Ensures macOS and Windows tests run sequentially to avoid MailSlurp race conditions
- Prevents OTP emails being consumed by wrong test when tests run in parallel

Author: CodeSchwert

.github/workflows/ui-tests.yml

@@ -91,7 +91,7 @@ jobs:
           #   runs-on: [ self-hosted, macOS ]
           #   test_script: browserstack-sdk pytest -s ./test/test_android.py --browserstack.config "browserstack.android.yml"
     concurrency:
-      group: test-${{ matrix.targetPlatform }}
+      group: ui-tests-email-inbox
     runs-on: ${{ matrix.runs-on }}
     steps:
       - uses: actions/checkout@v3