test(tui): fix type-ignore violation in tdd block cursor navigation steps

Remove disallowed # type: ignore[import-untyped] comment from behave
import in tdd_tui_block_cursor_navigation_steps.py, consistent with
all other step definition files in the project.

All local quality gates pass: lint, typecheck, security_scan,
dead_code, complexity, format.

features/steps/tdd_tui_block_cursor_navigation_steps.py

@@ -16,7 +16,7 @@ from __future__ import annotations
 
 from typing import Any
 
-from behave import then, when  # type: ignore[import-untyped]
+from behave import then, when
 
 
 @when("I inspect the TUI app BINDINGS for block cursor navigation")