Misc: CONTRIBUTING: Moves the Optional section above the macOS section for consistency (#4140)

Removes the optional section duplication from contributing documentation

Author: antonis

CONTRIBUTING.md

@@ -100,6 +100,7 @@ cd samples/react-native-macos/
 yarn
 bundle install
 yarn pod-install-legacy
+yarn start
 ```
 
 You can now build and run the project from command line:
@@ -111,21 +112,6 @@ or by openning the `samples/react-native-macos/macos/sentry-react-native-sample.
 
 _Note that the new architecture is not supported for the macOS sample at this point._
 
-### Optional
-
-You can optionally start the Metro bundler if you want to control where it runs:
-
-```sh
-yarn start --reset-cache
-```
-
-Run the emulators:
-
-```sh
-yarn react-native run-ios
-yarn react-native run-android
-```
-
 ## Develop with sentry-cocoa
 
 Here are step on how to test your changes in `sentry-cocoa` with `sentry-react-native`. We assume you have both repositories cloned in siblings folders.