data store: fix incorrect task state (#5650)

data store: fix issue where task status didn't update in a timely fashion

Closes #5645

changes.d/5650.fix.md

@@ -0,0 +1 @@
+Fix a bug preventing clean-up of finished tasks in the GUI and TUI.

cylc/flow/scheduler.py

@@ -1755,10 +1755,11 @@ async def main_loop(self) -> None:
                     self.timers[self.EVENT_RESTART_TIMEOUT].stop()
                     self.is_restart_timeout_wait = False
 
-            if has_updated:
+            if has_updated or self.data_store_mgr.updates_pending:
                 # Update the datastore.
                 await self.update_data_structure(self.is_reloaded)
 
+            if has_updated:
                 if not self.is_reloaded:
                     # (A reload cannot un-stall workflow by itself)
                     self.is_stalled = False
@@ -1846,21 +1847,18 @@ def _update_workflow_state(self):
 
     async def update_data_structure(self, reloaded: bool = False):
         """Update DB, UIS, Summary data elements"""
-        # Add tasks that have moved from runahead to live pool.
-        if self.data_store_mgr.updates_pending:
-            # Collect/apply data store updates/deltas
-            self.data_store_mgr.update_data_structure(reloaded=reloaded)
-            # Publish updates:
-            if self.data_store_mgr.publish_pending:
-                self.data_store_mgr.publish_pending = False
-                self.server.publish_queue.put(
-                    self.data_store_mgr.publish_deltas)
-                # Non-async sleep - yield to other threads rather
-                # than event loop
-                sleep(0)
+        # Collect/apply data store updates/deltas
+        self.data_store_mgr.update_data_structure(reloaded=reloaded)
+        # Publish updates:
+        if self.data_store_mgr.publish_pending:
+            self.data_store_mgr.publish_pending = False
+            self.server.publish_queue.put(
+                self.data_store_mgr.publish_deltas)
+            # Non-async sleep - yield to other threads rather
+            # than event loop
+            sleep(0)
         # Database update
         self.workflow_db_mgr.put_task_pool(self.pool)
-        self.update_data_store()
 
     def check_workflow_timers(self):
         """Check timers, and abort or run event handlers as configured."""