[TEST] illegal_argument_exception when downsampling all indexes in …

…serverless (elastic#99630)

Downsampling wildcard and _all indexes raises different errors in
stateful (security disabled) vs serverless (security enabled):

Stateful:

```
[{type=index_not_found_exception, reason=no such index [test*], index_uuid=_na_, index=test*, stack_trace=[test*] org.elasticsearch.index.IndexNotFoundException: no such index [test*]\n\tat org.elasticsearch.xpack.downsample.TransportDownsampleAction.masterOperation(TransportDownsampleAction.java:205)
```

Serverless:

```
[{type=illegal_argument_exception, reason=the action indices:admin/xpack/downsample does not support wildcards; the provided index expression(s) [test*] are not allowed, stack_trace=org.elasticsearch.ElasticsearchException$1: the action indices:admin/xpack/downsample does not support wildcards; the provided index expression(s) [test*] are not allowed
```

x-pack/plugin/downsample/qa/rest/src/yamlRestTest/resources/rest-api-spec/test/downsample/10_basic.yml

@@ -444,8 +444,10 @@ setup:
         body:
           index.blocks.write: true
 
+  # The following two tests may return different exceptions, depending on whether security is enabled (serverless)
+  # or not (stateful).
   - do:
-      catch: /index_not_found_exception/
+      catch: /index_not_found_exception|illegal_argument_exception/
       indices.downsample:
         index: test*
         target_index: test-downsample
@@ -455,7 +457,7 @@ setup:
           }
 
   - do:
-      catch: /index_not_found_exception/
+      catch: /index_not_found_exception|illegal_argument_exception/
       indices.downsample:
         index: _all
         target_index: test-downsample