dart.flutter add url_prefix (#13797)

adding URL prefix

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Co-authored-by: Giancarlo Buenaflor <[email protected]>

Author: rodolfoBee

platform-includes/debug-symbols/dart-plugin/dart.flutter.mdx

@@ -126,6 +126,7 @@ The following table lists all available configuration options for the Sentry Dar
 | `upload_source_maps` | boolean | `false` | Enables or disables automatic upload of source maps | |
 | `upload_sources` | boolean | `false` | Enables or disables source code upload | |
 | `url` | string | | The URL of your Sentry instance | `SENTRY_URL` |
+| `url_prefix` | URL prefix for JS source maps | e.g. ~/app/ (string) | no | - |
 | `wait_for_processing` | boolean | `false` | Whether to wait for server-side processing of uploaded files | |
 | `log_level` | string | `warn` | Configures the log level for sentry-cli (`trace`, `debug`, `info`, `warn`, `error`) | `SENTRY_LOG_LEVEL` |
 | `release` | string | `name@version` from pubspec | The release version for source maps | `SENTRY_RELEASE` |