[network-connections-api] Update description with group_by limit (#3247)

Co-authored-by: ci.datadog-api-spec <packages@datadoghq.com>

Author: api-clients-generation-pipeline[bot]

.generated-info

@@ -1,4 +1,4 @@
 {
-  "spec_repo_commit": "b737cc4",
-  "generated": "2025-07-28 13:12:54.236"
+  "spec_repo_commit": "0fe80dc",
+  "generated": "2025-07-28 18:49:45.067"
 }

.generator/schemas/v2/openapi.yaml

@@ -55082,7 +55082,8 @@ paths:
         schema:
           format: int64
           type: integer
-      - description: Comma-separated list of fields to group connections by.
+      - description: Comma-separated list of fields to group connections by. The maximum
+          number of group_by(s) is 10.
         in: query
         name: group_by
         schema: