Add notice about env variable allowing to enable debug sym upload

Author: tustanivsky

docs/platforms/unreal/configuration/debug-symbols/index.mdx

@@ -21,6 +21,8 @@ You must configure which build configurations, target types, and platforms Sentr
 
 ![The Unreal Engine debug symbols upload configuration](./img/unreal-debug-symbols.png)
 
+Alternatively, debug symbol upload can be enabled by setting `SENTRY_UPLOAD_SYMBOLS_AUTOMATICALLY` environment variable to `True`. This can be especially helpful in CI/CD environments where manual configuration is impractical.
+
 ### Manual Upload Using sentry-cli
 
 To upload debug symbols to Sentry manually, run `sentry-cli` through the command line. You can either use the provided executables from within the package, or follow the [sentry-cli documentation](/product/cli/installation/) to make it available globally. To upload debug symbols run the following command: