CI(trigger-e2e-tests): check permissions before running jobs (#10785)

## Problem

PRs created by external contributors, in some cases might list failed
jobs
- `Trigger E2E Tests / cancel-previous-e2e-tests`
- `Trigger E2E Tests / tag`

They don't block the merge, and tests in fact pass (their counterparts
in internal PR), but because jobs are triggered from an external PR (and
not from the corresponding internal one) they still present as red
marks.

For example https://github.com/neondatabase/neon/pull/10778

## Summary of changes
- Check permissions before triggering e2e tests

.github/workflows/trigger-e2e-tests.yml

@@ -15,7 +15,14 @@ env:
   E2E_CONCURRENCY_GROUP: ${{ github.repository }}-e2e-tests-${{ github.ref_name }}-${{ github.ref_name == 'main' && github.sha || 'anysha' }}
 
 jobs:
+  check-permissions:
+    if: ${{ !contains(github.event.pull_request.labels.*.name, 'run-no-ci') }}
+    uses: ./.github/workflows/check-permissions.yml
+    with:
+      github-event-name: ${{ github.event_name }}
+
   cancel-previous-e2e-tests:
+    needs: [ check-permissions ]
     if: github.event_name == 'pull_request'
     runs-on: ubuntu-22.04
 
@@ -29,6 +36,7 @@ jobs:
               --field concurrency_group="${{ env.E2E_CONCURRENCY_GROUP }}"
 
   tag:
+    needs: [ check-permissions ]
     runs-on: ubuntu-22.04
     outputs:
       build-tag: ${{ steps.build-tag.outputs.tag }}