fix(harbor): correct secret key name for core secret

Harbor Helm chart expects 'secret' key not 'CORE_SECRET' for the
CORE_SECRET environment variable. This was causing jobservice pod
to fail with CreateContainerConfigError.

Fixes: harbor-jobservice-757bbf44cc-tvznq error

cluster/platform/harbor/externalsecret.yaml

@@ -36,7 +36,8 @@ spec:
         key: the-seas
         property: redis-password
     
-    - secretKey: CORE_SECRET
+    # Core secret - Harbor Helm chart expects key named 'secret' not 'CORE_SECRET'
+    - secretKey: secret
       remoteRef:
         key: the-seas
         property: core-secret