test(e2e): give the generator leg aws credentials

The ecr and sts generators mint tokens against real AWS, so the generator leg
needs the aws secret group in addition to grafana. Without it the ecr spec
failed once the leg ran in isolation.

Signed-off-by: Alexander Chernov <alexander@chernov.it>

e2e/matrix.yaml

@@ -173,14 +173,13 @@ areas:
 
   # Non-provider suites. No provider labels, so providers is empty; they run the
   # whole non-managed suite. flux and argocd exercise ESO under GitOps tools and
-  # need no creds. generator's grafana specs need the grafana group; the
-  # credential needs of the other generators (e.g. ecr/sts) want a closer look
-  # before this leg is enabled.
+  # need no creds. The generator suite needs grafana (grafana generator) and aws
+  # (the ecr and sts generators mint tokens against real AWS).
   - name: generator
     suite: generator
     labels: "!managed"
     providers: []
-    secret_groups: [grafana]
+    secret_groups: [grafana, aws]
     needs_secrets: true
     paths:
       - "apis/**"