test: fix progress notification assertions for related_request_id (#2038)

Co-authored-by: Lee Hubbard <hubbard.zlee@unknowncyber.com>
Co-authored-by: Max Isbey <224885523+maxisbey@users.noreply.github.com>

src/mcp/server/mcpserver/server.py

@@ -1163,6 +1163,7 @@ class Context(BaseModel, Generic[LifespanContextT, RequestT]):
             progress=progress,
             total=total,
             message=message,
+            related_request_id=self.request_id,
         )
 
     async def read_resource(self, uri: str | AnyUrl) -> Iterable[ReadResourceContents]: