Build/Test Tools: Temporarily ignore Slack failures.

When many workflows are initiated at the same time, there are often instances where the requests to Slack providing updates are rate limited. This usually happens when the Test Old Branches workflow runs and initiates testing for all workflows in branches that could potentially receive a security update.

Even though everything was successful in the workflow except the message, the workflow run is marked as failed. The next time the same workflow runs for that branch, a “fixed” message will be sent to `#core` in Slack. The result is a burst of messages that is quite noisy and unnecessary.

This temporarily adds `continue-on-error` to the jobs responsible for sending the messages until a better solution can be decided on.

See #61701.

git-svn-id: https://develop.svn.wordpress.org/trunk@59209 602fd350-edb4-49c9-b593-d223f7449a82

Author: desrosj

.github/workflows/slack-notifications.yml

@@ -161,6 +161,7 @@ jobs:
   failure:
     name: Failure notifications
     runs-on: ubuntu-latest
+    continue-on-error: true
     timeout-minutes: 5
     needs: [ prepare ]
     if: ${{ needs.prepare.outputs.previous_conclusion != 'first-failure' && inputs.calling_status == 'failure' || failure() }}
@@ -177,6 +178,7 @@ jobs:
   fixed:
     name: Fixed notifications
     runs-on: ubuntu-latest
+    continue-on-error: true
     timeout-minutes: 5
     needs: [ prepare ]
     if: ${{ contains( fromJson( '["failure", "cancelled", "none"]' ), needs.prepare.outputs.previous_conclusion ) && inputs.calling_status == 'success' && success() }}
@@ -193,6 +195,7 @@ jobs:
   success:
     name: Success notifications
     runs-on: ubuntu-latest
+    continue-on-error: true
     timeout-minutes: 5
     needs: [ prepare ]
     if: ${{ inputs.calling_status == 'success' && success() }}
@@ -209,6 +212,7 @@ jobs:
   cancelled:
     name: Cancelled notifications
     runs-on: ubuntu-latest
+    continue-on-error: true
     timeout-minutes: 5
     needs: [ prepare ]
     if: ${{ inputs.calling_status == 'cancelled' || cancelled() }}