Avoid import of pkg_resource with Starlette integration (#1836)

By changing the order in the condition, we can avoid the call to
`_get_installed_modules` (which imports `pkg_resources`) when the
`mechanism_type` is set to `"starlette"`.

Co-authored-by: Anton Pirker <anton.pirker@sentry.io>

sentry_sdk/integrations/asgi.py

@@ -109,7 +109,7 @@ def __init__(
             )
 
         asgi_middleware_while_using_starlette_or_fastapi = (
-            "starlette" in _get_installed_modules() and mechanism_type == "asgi"
+            mechanism_type == "asgi" and "starlette" in _get_installed_modules()
         )
         if asgi_middleware_while_using_starlette_or_fastapi:
             logger.warning(