fix(backend): Cleanup service on service closure (#9735)

The cleanup command was only called on SIGTERM, making it possible for
the service to close without being cleaned. Risking the connection not
being proactively closed when the service is unused.

### Changes 🏗️

Call the cleanup command on the service finally block.

### 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] Run the service, stop it, see the log is printed (locally)

autogpt_platform/backend/backend/util/process.py

@@ -28,6 +28,7 @@ class AppProcess(ABC):
     """
 
     process: Optional[Process] = None
+    cleaned_up = False
 
     set_start_method("spawn", force=True)
     configure_logging()
@@ -62,6 +63,7 @@ class AppProcess(ABC):
 
     def execute_run_command(self, silent):
         signal.signal(signal.SIGTERM, self._self_terminate)
+        signal.signal(signal.SIGINT, self._self_terminate)
 
         try:
             if silent:
@@ -73,9 +75,16 @@ class AppProcess(ABC):
             self.run()
         except (KeyboardInterrupt, SystemExit) as e:
             logger.warning(f"[{self.service_name}] Terminated: {e}; quitting...")
+        finally:
+            if not self.cleaned_up:
+                self.cleanup()
+                self.cleaned_up = True
+            logger.info(f"[{self.service_name}] Terminated.")
 
     def _self_terminate(self, signum: int, frame):
-        self.cleanup()
+        if not self.cleaned_up:
+            self.cleanup()
+            self.cleaned_up = True
         sys.exit(0)
 
     # Methods that are executed OUTSIDE the process #