Fix type checking issue with service_ports

This worked in Pyright 1.1.314, but not in 1.1.315 or 1.1.316.

The type of service_ports is
List[Tuple[str, Literal[3000], Literal[3000]]], which doesn't type
check as List[Tuple[str, int, int]] -- which is very unintuitive, but
oh well.

I believe this is by design, see
microsoft/pyright#5366 and
https://microsoft.github.io/pyright/#/type-inference?id=tuple-expressions

The Pyright fixes were probably one of
microsoft/pyright#5321 or
microsoft/pyright#5323

src/charm.py

@@ -29,7 +29,7 @@
 import time
 from io import StringIO
 from pathlib import Path
-from typing import Any, Callable, Dict
+from typing import Any, Callable, Dict, List, Tuple
 from urllib.parse import ParseResult, urlparse
 
 import yaml
@@ -573,7 +573,7 @@ def _on_dashboards_changed(self, event) -> None:
     def _patch_k8s_service(self):
         """Fix the Kubernetes service that was setup by Juju with correct port numbers."""
         if self.unit.is_leader() and not self._stored.k8s_service_patched:  # type: ignore[truthy-function]
-            service_ports = [
+            service_ports: List[Tuple[str, int, int]] = [
                 (self.app.name, PORT, PORT),
             ]
             try: