Constrain when we emit webhooks for retried tests (#24484)

* Constrain when we emit webhooks for retried tests

Only send webhooks (notifying all staff developers) only for retried tests on `master` and `release-*`.

* drop @devs at-mention

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

.github/workflows/server-test-template.yml

@@ -76,12 +76,12 @@ jobs:
           report_paths: server/report.xml
           check_name: ${{ inputs.name }} (Results)
           require_tests: true
-      - name: Report retried tests via webhook
-        if: ${{ steps.report.outputs.retried > 0 }}
+      - name: Report retried tests via webhook (master || release-*)
+        if: ${{ steps.report.outputs.retried > 0 && (github.ref_name == 'master' || startsWith(github.ref_name, 'release-')) }}
         run: |
           curl \
             --fail \
             -X POST \
             -H "Content-Type: application/json" \
-            -d "{\"text\":\"#### ⚠️  One or more flaky tests detected ⚠️\\n* Failing job: [github.com/mattermost/mattermost:${{ inputs.name }}](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})\\n* If this is your pull request, double check your code to ensure you haven't introduced a flaky test.\\n* If this occurred on master or a release branch, reply to this message if you're willing to help.\\n* Submit a separate pull request to skip the flaky tests (e.g. [23360](https://github.com/mattermost/mattermost/pull/23360)) and file JIRA ticket (e.g. [MM-52743](https://mattermost.atlassian.net/browse/MM-52743)) for later investigation.\\n* Finally, reply to this message with a link to the created JIRA ticket.\\ncc @devs\"}" \
+            -d "{\"text\":\"#### ⚠️  One or more flaky tests detected ⚠️\\n* Failing job: [github.com/mattermost/mattermost:${{ inputs.name }}](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})\\n* If this is your pull request, double check your code to ensure you haven't introduced a flaky test.\\n* If this occurred on master or a release branch, reply to this message if you're willing to help.\\n* Submit a separate pull request to skip the flaky tests (e.g. [23360](https://github.com/mattermost/mattermost/pull/23360)) and file JIRA ticket (e.g. [MM-52743](https://mattermost.atlassian.net/browse/MM-52743)) for later investigation.\\n* Finally, reply to this message with a link to the created JIRA ticket.\\n\"}" \
             ${{ secrets.MM_COMMUNITY_DEVELOPERS_INCOMING_WEBHOOK_FROM_GH_ACTIONS }}