Python: Fix integration test check for PRs (#2490)

### Motivation and Context

Python integration test check resolves the MSTEAM_WEBHOOK as "" when run
for PRs. The secret is not needed in this scenario, but the value should
be non ""

### Description

### Contribution Checklist

<!-- Before submitting this PR, please make sure: -->

- [ ] The code builds clean without any errors or warnings
- [ ] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [ ] All unit tests pass, and I have added new tests where possible
- [ ] I didn't break anyone 😄

.github/workflows/python-integration-tests.yml

@@ -183,10 +183,20 @@ jobs:
 
       - name: Microsoft Teams Notification
         uses: skitionek/notify-microsoft-teams@master
-        if: always()
+        if: github.ref == 'refs/heads/main'
         with:
           webhook_url: ${{ secrets.MSTEAMS_WEBHOOK }}
           dry_run: ${{ env.run_type != 'Daily' && env.run_type != 'Manual'}}
           job: ${{ toJson(job) }}
           steps: ${{ toJson(steps) }}
           overwrite: "{title: ` ${{ env.run_type }}: ${{ env.date }} `, text: ` ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}`}"
+
+      - name: Microsoft Teams Notification (Dry Run)
+        uses: skitionek/notify-microsoft-teams@master
+        if: github.ref != 'refs/heads/main'
+        with:
+          webhook_url: NONE
+          dry_run: ${{ env.run_type != 'Daily' && env.run_type != 'Manual'}}
+          job: ${{ toJson(job) }}
+          steps: ${{ toJson(steps) }}
+          overwrite: "{title: ` ${{ env.run_type }}: ${{ env.date }} `, text: ` ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}`}"