chore(starlette): Disable middleware spans by default (#5224)

Closes #5109

Author: alexander-alderman-webb

sentry_sdk/integrations/starlette.py

@@ -89,7 +89,7 @@ def __init__(
         self,
         transaction_style="url",  # type: str
         failed_request_status_codes=_DEFAULT_FAILED_REQUEST_STATUS_CODES,  # type: Union[Set[int], list[HttpStatusCodeRange], None]
-        middleware_spans=True,  # type: bool
+        middleware_spans=False,  # type: bool
         http_methods_to_capture=DEFAULT_HTTP_METHODS_TO_CAPTURE,  # type: tuple[str, ...]
     ):
         # type: (...) -> None

tests/integrations/starlette/test_starlette.py

@@ -646,7 +646,7 @@ def test_user_information_transaction_no_pii(sentry_init, capture_events):
 def test_middleware_spans(sentry_init, capture_events):
     sentry_init(
         traces_sample_rate=1.0,
-        integrations=[StarletteIntegration()],
+        integrations=[StarletteIntegration(middleware_spans=True)],
     )
     starlette_app = starlette_app_factory(
         middleware=[Middleware(AuthenticationMiddleware, backend=BasicAuthBackend())]