reflect auto-detection (#6426)

other framework specific snippetes reflect the SDKs auto-detection for enabling integrations. Updating Flask to do the same

Author: smeubank

src/platform-includes/getting-started-config/python.flask.mdx

@@ -1,13 +1,9 @@
 ```python
 import sentry_sdk
 from flask import Flask
-from sentry_sdk.integrations.flask import FlaskIntegration
 
 sentry_sdk.init(
     dsn="___PUBLIC_DSN___",
-    integrations=[
-        FlaskIntegration(),
-    ],
 
     # Set traces_sample_rate to 1.0 to capture 100%
     # of transactions for performance monitoring.