chore(cleanup)!: remove tool_runtime.rag_tool (#3871)

Kill the `builtin::rag` tool group completely since it is no longer
targeted. We use the Responses implementation for knowledge_search which
uses the `openai_vector_stores` pathway.

---------

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

llama_stack/distributions/watsonx/build.yaml

@@ -23,7 +23,6 @@ distribution_spec:
     tool_runtime:
     - provider_type: remote::brave-search
     - provider_type: remote::tavily-search
-    - provider_type: inline::rag-runtime
     - provider_type: remote::model-context-protocol
     files:
     - provider_type: inline::localfs

llama_stack/distributions/watsonx/run.yaml

@@ -83,8 +83,6 @@ providers:
     config:
       api_key: ${env.TAVILY_SEARCH_API_KEY:=}
       max_results: 3
-  - provider_id: rag-runtime
-    provider_type: inline::rag-runtime
   - provider_id: model-context-protocol
     provider_type: remote::model-context-protocol
   files:
@@ -125,8 +123,6 @@ registered_resources:
   tool_groups:
   - toolgroup_id: builtin::websearch
     provider_id: tavily-search
-  - toolgroup_id: builtin::rag
-    provider_id: rag-runtime
 server:
   port: 8321
 telemetry:

llama_stack/distributions/watsonx/watsonx.py

@@ -33,7 +33,6 @@ def get_distribution_template(name: str = "watsonx") -> DistributionTemplate:
         "tool_runtime": [
             BuildProvider(provider_type="remote::brave-search"),
             BuildProvider(provider_type="remote::tavily-search"),
-            BuildProvider(provider_type="inline::rag-runtime"),
             BuildProvider(provider_type="remote::model-context-protocol"),
         ],
         "files": [BuildProvider(provider_type="inline::localfs")],
@@ -50,10 +49,6 @@ def get_distribution_template(name: str = "watsonx") -> DistributionTemplate:
             toolgroup_id="builtin::websearch",
             provider_id="tavily-search",
         ),
-        ToolGroupInput(
-            toolgroup_id="builtin::rag",
-            provider_id="rag-runtime",
-        ),
     ]
 
     files_provider = Provider(