Allow (un)block_room storage functions to be called on workers (#18119)

This is so workers can call these functions.

This was preventing the [Delete Room Admin
API](https://element-hq.github.io/synapse/latest/admin_api/rooms.html#version-2-new-version)
from succeeding when `block: true` was specified. This was because we
had `run_background_tasks_on` configured to run on a separate worker.

As workers weren't able to call the `block_room` storage function before
this PR, the (delete room) task failed when taken off the queue by the
worker.

changelog.d/18119.bugfix

@@ -0,0 +1 @@
+Fix a bug where the [Delete Room Admin API](https://element-hq.github.io/synapse/latest/admin_api/rooms.html#version-2-new-version) would fail if the `block` parameter was set to `true` and a worker other than the main process was configured to handle background tasks.

synapse/storage/databases/main/room.py

@@ -1181,6 +1181,50 @@ def _quarantine_media_txn(
 
         return total_media_quarantined
 
+    async def block_room(self, room_id: str, user_id: str) -> None:
+        """Marks the room as blocked.
+
+        Can be called multiple times (though we'll only track the last user to
+        block this room).
+
+        Can be called on a room unknown to this homeserver.
+
+        Args:
+            room_id: Room to block
+            user_id: Who blocked it
+        """
+        await self.db_pool.simple_upsert(
+            table="blocked_rooms",
+            keyvalues={"room_id": room_id},
+            values={},
+            insertion_values={"user_id": user_id},
+            desc="block_room",
+        )
+        await self.db_pool.runInteraction(
+            "block_room_invalidation",
+            self._invalidate_cache_and_stream,
+            self.is_room_blocked,
+            (room_id,),
+        )
+
+    async def unblock_room(self, room_id: str) -> None:
+        """Remove the room from blocking list.
+
+        Args:
+            room_id: Room to unblock
+        """
+        await self.db_pool.simple_delete(
+            table="blocked_rooms",
+            keyvalues={"room_id": room_id},
+            desc="unblock_room",
+        )
+        await self.db_pool.runInteraction(
+            "block_room_invalidation",
+            self._invalidate_cache_and_stream,
+            self.is_room_blocked,
+            (room_id,),
+        )
+
     async def get_rooms_for_retention_period_in_range(
         self, min_ms: Optional[int], max_ms: Optional[int], include_null: bool = False
     ) -> Dict[str, RetentionPolicy]:
@@ -2500,50 +2544,6 @@ async def add_room_report(
         )
         return next_id
 
-    async def block_room(self, room_id: str, user_id: str) -> None:
-        """Marks the room as blocked.
-
-        Can be called multiple times (though we'll only track the last user to
-        block this room).
-
-        Can be called on a room unknown to this homeserver.
-
-        Args:
-            room_id: Room to block
-            user_id: Who blocked it
-        """
-        await self.db_pool.simple_upsert(
-            table="blocked_rooms",
-            keyvalues={"room_id": room_id},
-            values={},
-            insertion_values={"user_id": user_id},
-            desc="block_room",
-        )
-        await self.db_pool.runInteraction(
-            "block_room_invalidation",
-            self._invalidate_cache_and_stream,
-            self.is_room_blocked,
-            (room_id,),
-        )
-
-    async def unblock_room(self, room_id: str) -> None:
-        """Remove the room from blocking list.
-
-        Args:
-            room_id: Room to unblock
-        """
-        await self.db_pool.simple_delete(
-            table="blocked_rooms",
-            keyvalues={"room_id": room_id},
-            desc="unblock_room",
-        )
-        await self.db_pool.runInteraction(
-            "block_room_invalidation",
-            self._invalidate_cache_and_stream,
-            self.is_room_blocked,
-            (room_id,),
-        )
-
     async def clear_partial_state_room(self, room_id: str) -> Optional[int]:
         """Clears the partial state flag for a room.