CI: cancel old e2e-tests on new commits (#6463)

## Problem

Triggered `e2e-tests` job is not cancelled along with other jobs in a PR
if the PR get new commits. We can improve the situation by setting
`concurrency_group` for the remote workflow
(https://github.com/neondatabase/cloud/pull/9622 adds
`concurrency_group` group input to the remote workflow).

Ref https://neondb.slack.com/archives/C059ZC138NR/p1706087124297569

Cloud's part added in https://github.com/neondatabase/cloud/pull/9622

## Summary of changes
- Set `concurrency_group` parameter when triggering `e2e-tests`
- At the beginning of a CI pipeline, trigger Cloud's
`cancel-previous-in-concurrency-group.yml` workflow which cancels
previously triggered e2e-tests

.github/workflows/build_and_test.yml

@@ -22,6 +22,8 @@ env:
   AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_DEV }}
   AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_KEY_DEV }}
   NEXTEST_RETRIES: 3
+  # A concurrency group that we use for e2e-tests runs, matches `concurrency.group` above with `github.repository` as a prefix
+  E2E_CONCURRENCY_GROUP: ${{ github.repository }}-${{ github.workflow }}-${{ github.ref_name }}-${{ github.ref_name == 'main' && github.sha || 'anysha' }}
 
 jobs:
   check-permissions:
@@ -45,6 +47,20 @@ jobs:
 
         exit 1
 
+  cancel-previous-e2e-tests:
+    needs: [ check-permissions ]
+    if: github.event_name == 'pull_request'
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Cancel previous e2e-tests runs for this PR
+        env:
+          GH_TOKEN: ${{ secrets.CI_ACCESS_TOKEN }}
+        run: |
+          gh workflow --repo neondatabase/cloud \
+            run cancel-previous-in-concurrency-group.yml \
+              --field concurrency_group="${{ env.E2E_CONCURRENCY_GROUP }}"
+
   tag:
     needs: [ check-permissions ]
     runs-on: [ self-hosted, gen3, small ]
@@ -696,7 +712,8 @@ jobs:
                 \"commit_hash\": \"$COMMIT_SHA\",
                 \"remote_repo\": \"${{ github.repository }}\",
                 \"storage_image_tag\": \"${{ needs.tag.outputs.build-tag }}\",
-                \"compute_image_tag\": \"${{ needs.tag.outputs.build-tag }}\"
+                \"compute_image_tag\": \"${{ needs.tag.outputs.build-tag }}\",
+                \"concurrency_group\": \"${{ env.E2E_CONCURRENCY_GROUP }}\"
               }
             }"