fix(sdk/crewai): split EventBusListener import + attr-defined ignore on module

CI ruff check src/ fails on the 0.13.9-rc3 candidate
with:

  I001 Import block is un-sorted or un-formatted
    --> src/nullrun/instrumentation/crewai.py:187:9

The two from crewai.events.* import lines had to share an
import block per isort default rules — but the existing
type-ignore comments attached them to a single line, which
ruff flagged. ruff check --fix collapses the second line
into a multi-line parenthesised block, but the
# type: ignore[attr-defined] then lands on the attribute
line (EventBusListener) instead of the module line, and
mypy needs it on the module line to silence the
"Module has no attribute 'EventBusListener'" error.

Fix: split the import into a parenthesised block and put the
attr-defined ignore on the module-level line, not the
attribute line. Ruff is now satisfied (single block, sorted)
and mypy is also satisfied (attr-defined error suppressed
at the correct scope).

Local verification:
  * ruff check src/ — "All checks passed!".
  * mypy src/nullrun/instrumentation/crewai.py —
    "Success: no issues found in 1 source file".
  * pytest tests/test_crewai_patch.py
    tests/test_runtime.py tests/test_runtime_branches.py
    test_track_batch_retry.py test_track_span_context.py
    test_v3_wire_contract.py —
    142 passed, 1 skipped, 2 warnings.

No runtime change; pure lint/typing patch.

Author: maltsev-dev

src/nullrun/instrumentation/crewai.py

@@ -185,7 +185,9 @@ def patch_crewai(runtime: Any) -> bool:
 
     try:
         from crewai.events import crewai_event_bus  # type: ignore[import-not-found]
-        from crewai.events.event_bus import EventBusListener  # type: ignore[import-not-found,attr-defined]
+        from crewai.events.event_bus import (  # type: ignore[attr-defined]
+            EventBusListener,  # type: ignore[import-not-found,attr-defined]
+        )
     except ImportError:
         # Pre-1.15 crewai lacks the event bus. Fall through to the
         # legacy callback injection so old versions still get