QA: Migrate type checker from mypy to ty, CodeRabbit improvements 3

Author: amotl

cratedb_toolkit/testing/testcontainers/util.py

@@ -177,7 +177,7 @@ class PytestTestcontainerAdapter:
     """
 
     def __init__(self):
-        self.container: DbContainer
+        self.container: t.Optional[DbContainer] = None
         self.run_setup()
 
     @abstractmethod
@@ -205,7 +205,11 @@ def run_setup(self):
         self.start()
 
     def start(self):
+        if self.container is None:
+            raise ValueError("Container not initialized")
         self.container.start()
 
     def stop(self):
+        if self.container is None:
+            raise ValueError("Container not initialized")
         self.container.stop()