fix: fix jobs api literal return type (#1757)

# What does this PR do?

- We cannot directly return a literal type

> Note: this is not final jobs API change

[//]: # (If resolving an issue, uncomment and update the line below)
[//]: # (Closes #[issue-number])

## Test Plan
<img width="837" alt="image"
src="https://github.com/user-attachments/assets/18a17561-35f9-443d-987d-54afdd6ff40c"
/>


[//]: # (## Documentation)

docs/_static/llama-stack-spec.yaml

@@ -1491,7 +1491,7 @@ paths:
           content:
             application/json:
               schema:
-                $ref: '#/components/schemas/JobStatus'
+                $ref: '#/components/schemas/Job'
         '400':
           $ref: '#/components/responses/BadRequest400'
         '429':
@@ -5277,21 +5277,19 @@ components:
         - checkpoints
       title: PostTrainingJobArtifactsResponse
       description: Artifacts of a finetuning job.
-    JobStatus:
-      type: string
-      enum:
-        - completed
-        - in_progress
-        - failed
-        - scheduled
-      title: JobStatus
     PostTrainingJobStatusResponse:
       type: object
       properties:
         job_uuid:
           type: string
         status:
-          $ref: '#/components/schemas/JobStatus'
+          type: string
+          enum:
+            - completed
+            - in_progress
+            - failed
+            - scheduled
+          title: JobStatus
         scheduled_at:
           type: string
           format: date-time
@@ -5556,6 +5554,24 @@ components:
         - data
       title: IterrowsResponse
       description: A paginated list of rows from a dataset.
+    Job:
+      type: object
+      properties:
+        job_id:
+          type: string
+        status:
+          type: string
+          enum:
+            - completed
+            - in_progress
+            - failed
+            - scheduled
+          title: JobStatus
+      additionalProperties: false
+      required:
+        - job_id
+        - status
+      title: Job
     ListAgentSessionsResponse:
       type: object
       properties:
@@ -6550,15 +6566,6 @@ components:
       required:
         - benchmark_config
       title: RunEvalRequest
-    Job:
-      type: object
-      properties:
-        job_id:
-          type: string
-      additionalProperties: false
-      required:
-        - job_id
-      title: Job
     RunShieldRequest:
       type: object
       properties: