feat: create HTTP DELETE API endpoints to unregister ScoringFn and Benchmark resources in Llama Stack (#3371)

# What does this PR do?
<!-- Provide a short summary of what this PR does and why. Link to
relevant issues if applicable. -->
This PR provides functionality for users to unregister ScoringFn and
Benchmark resources for `scoring` and `eval` APIs.

<!-- If resolving an issue, uncomment and update the line below -->
<!-- Closes #[issue-number] -->
Closes #3051 

## Test Plan
<!-- Describe the tests you ran to verify your changes with result
summaries. *Provide clear instructions so the plan can be easily
re-executed.* -->
Updated integration and unit tests via CI workflow

docs/_static/llama-stack-spec.yaml

@@ -954,6 +954,30 @@ paths:
           required: true
           schema:
             type: string
+    delete:
+      responses:
+        '200':
+          description: OK
+        '400':
+          $ref: '#/components/responses/BadRequest400'
+        '429':
+          $ref: >-
+            #/components/responses/TooManyRequests429
+        '500':
+          $ref: >-
+            #/components/responses/InternalServerError500
+        default:
+          $ref: '#/components/responses/DefaultError'
+      tags:
+        - Benchmarks
+      description: Unregister a benchmark.
+      parameters:
+        - name: benchmark_id
+          in: path
+          description: The ID of the benchmark to unregister.
+          required: true
+          schema:
+            type: string
   /v1/openai/v1/chat/completions/{completion_id}:
     get:
       responses:
@@ -1119,6 +1143,31 @@ paths:
           required: true
           schema:
             type: string
+    delete:
+      responses:
+        '200':
+          description: OK
+        '400':
+          $ref: '#/components/responses/BadRequest400'
+        '429':
+          $ref: >-
+            #/components/responses/TooManyRequests429
+        '500':
+          $ref: >-
+            #/components/responses/InternalServerError500
+        default:
+          $ref: '#/components/responses/DefaultError'
+      tags:
+        - ScoringFunctions
+      description: Unregister a scoring function.
+      parameters:
+        - name: scoring_fn_id
+          in: path
+          description: >-
+            The ID of the scoring function to unregister.
+          required: true
+          schema:
+            type: string
   /v1/shields/{identifier}:
     get:
       responses: