If a solution exists but we want to remove it it should be deleted from the remote (#200)

Author: ColdHeat

ctfcli/core/challenge.py

@@ -919,7 +919,9 @@ def sync(self, ignore: tuple[str] = ()) -> None:
             self._set_next(_next)
 
         if "solution" not in ignore:
-            # self._delete_existing_solution()
+            resolved_solution = self._resolve_solution_path()
+            if not resolved_solution:
+                self._delete_existing_solution()
             self._create_solution()
 
         make_challenge_visible = False