fix(shuffle-tests): Update the shuffle-test backend-test job definition to match definition in backend.yml (#82327)

<!-- Describe your PR here. -->
Shuffle tests are failing due to lower shard count and missing service
dependencies. Sync the backend-test job with the definition in
backend.yml
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Author: bc-sentry

.github/workflows/shuffle-tests.yml

@@ -28,18 +28,22 @@ jobs:
     name: run backend tests
     runs-on: ubuntu-24.04
     timeout-minutes: 90
+    permissions:
+      contents: read
+      id-token: write
     strategy:
       # This helps not having to run multiple jobs because one fails, thus, reducing resource usage
       # and reducing the risk that one of many runs would turn red again (read: intermittent tests)
       fail-fast: false
       matrix:
         # XXX: When updating this, make sure you also update MATRIX_INSTANCE_TOTAL.
-        instance: [0, 1, 2, 3, 4, 5, 6]
+        instance: [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
         pg-version: ['14']
 
     env:
-      # XXX: MATRIX_INSTANCE_TOTAL must be hardcoded to the length of strategy.matrix.instance.
-      MATRIX_INSTANCE_TOTAL: 7
+      # XXX: `MATRIX_INSTANCE_TOTAL` must be hardcoded to the length of `strategy.matrix.instance`.
+      # If this increases, make sure to also increase `flags.backend.after_n_builds` in `codecov.yml`.
+      MATRIX_INSTANCE_TOTAL: 11
 
     steps:
       - uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332 # v4.1.7
@@ -48,7 +52,10 @@ jobs:
         uses: ./.github/actions/setup-sentry
         id: setup
         with:
+          redis_cluster: true
+          kafka: true
           snuba: true
+          symbolicator: true
           # Right now, we run so few bigtable related tests that the
           # overhead of running bigtable in all backend tests
           # is way smaller than the time it would take to run in its own job.