feat: Document --raw flag on sentry-cli send-envelope (#6992)

Author: loewenheim

src/docs/product/cli/send-event.mdx

@@ -80,6 +80,12 @@ This argument can be also provided in the form of a glob, which will cause it to
 sentry-cli send-event "./events/*.json"
 ```
 
+If `send-event` is called with the `--raw` flag, the event will not be validated before being sent.
+
+```bash
+sentry-cli send-event --raw ./events/20211029150006.json
+```
+
 ## Specifying Releases
 
 Releases can be sent with the `--release` parameter. A default release is picked up automatically if you are using sentry-cli from within a git repository.