feat(backend): Make agent store data to be publicly accessible by non authenticated user (#9710)

This PR publicly exposes all the agents listed in the store to the
internet.

### Changes 🏗️

Remove the auth requirement for an agent to download the agent.

### Checklist 📋

#### For code changes:
- [x] I have clearly listed my changes in the PR description
- [x] I have made a test plan
- [x] I have tested my changes according to the test plan:
- [x] Accessing
`http://localhost:8006/api/store/download/agents/{agentId}` without
authorization key.

autogpt_platform/backend/backend/server/v2/store/db.py

@@ -1005,7 +1005,7 @@ async def get_my_agents(
 
 
 async def get_agent(
-    user_id: str,
+    user_id: str | None,
     store_listing_version_id: str,
 ) -> GraphModel:
     """Get agent using the version ID and store listing version ID."""

autogpt_platform/backend/backend/server/v2/store/routes.py

@@ -7,6 +7,7 @@ import autogpt_libs.auth.depends
 import autogpt_libs.auth.middleware
 import fastapi
 import fastapi.responses
+from autogpt_libs.auth.depends import auth_middleware, get_user_id
 
 import backend.data.block
 import backend.data.graph
@@ -639,9 +640,7 @@ async def generate_image(
     tags=["store", "public"],
 )
 async def download_agent_file(
-    user_id: typing.Annotated[
-        str, fastapi.Depends(autogpt_libs.auth.depends.get_user_id)
-    ],
+    request: fastapi.Request,
     store_listing_version_id: str = fastapi.Path(
         ..., description="The ID of the agent to download"
     ),
@@ -658,6 +657,10 @@ async def download_agent_file(
     Raises:
         HTTPException: If the agent is not found or an unexpected error occurs.
     """
+    try:
+        user_id = get_user_id(await auth_middleware(request))
+    except fastapi.HTTPException:
+        user_id = None
 
     graph_data = await backend.server.v2.store.db.get_agent(
         user_id=user_id,