chore(ci): push e2e logs to Loki (#471)

Configure e2e GH actions to push logs to Loki on failure. This is
configured only for e2e tests which are run as a result of merge to
`main` branch.

task: https://app.asana.com/0/1206208509925075/1206729533969884/f

.github/workflows/e2etest.yml

@@ -22,3 +22,12 @@ jobs:
           name: failed-logs
           path: test/e2e/failed-logs.txt
           retention-days: 3
+
+      - name: e2e-logs
+        if: failure()
+        uses: metrico/loki-action@V3.1
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          endpoint: ${{ secrets.LOGQL_ENDPOINT }}
+          username: ${{ secrets.LOGQL_USER }}
+          password: ${{ secrets.LOGQL_PASS }}