fix: remove blanket builtins.__import__ patch from test_tui_import_error

The test patched builtins.__import__ with a blanket ImportError, blocking
ALL imports. This broke mutmut's stats phase which needs working imports
for coverage tracking. Setting sys.modules["flameconnect.tui"] = None
alone is sufficient to trigger ImportError on `from flameconnect.tui import run_tui`.

Co-authored-by: deviantintegral <255023+deviantintegral@users.noreply.github.com>

Author: Copilot

tests/test_cli_commands.py

@@ -1443,7 +1443,6 @@ async def test_tui_import_error(self, capsys):
 
         with (
             patch.dict("sys.modules", {"flameconnect.tui": None}),
-            patch("builtins.__import__", side_effect=ImportError("no tui")),
             pytest.raises(SystemExit),
         ):
             await cmd_tui()