Remove RN patch

ios/patches/ios-legacy-build-system.patch

@@ -1,12 +0,0 @@
-diff --git a/node_modules/react-native/local-cli/runIOS/runIOS.js b/node_modules/react-native/local-cli/runIOS/runIOS.js
-index dfabb92b8..5b2714729 100644
---- a/node_modules/react-native/local-cli/runIOS/runIOS.js
-+++ b/node_modules/react-native/local-cli/runIOS/runIOS.js
-@@ -283,6 +283,7 @@ function buildProject(
-       configuration,
-       '-scheme',
-       scheme,
-+      '-UseModernBuildSystem=NO',
-       '-destination',
-       `id=${udid}`,
-       '-derivedDataPath',

scripts/prepare-for-platform.sh

@@ -79,10 +79,6 @@ case $1 in
         mv "$RCTSTATUS_DIR/$sourceBasename" "$RCTSTATUS_DIR/$targetBasename"
       fi
       if [ "$(uname)" == 'Darwin' ]; then
-        # TODO: remove this patch when we upgrade to a RN version that plays well with the modern build system
-        git apply --check $GIT_ROOT/ios/patches/ios-legacy-build-system.patch 2> /dev/null && \
-          git apply $GIT_ROOT/ios/patches/ios-legacy-build-system.patch || \
-          echo "Patch already applied"
         # CocoaPods are trash and can't handle other pod instances running at the same time
         $GIT_ROOT/scripts/wait-for.sh pod 240
         pushd $GIT_ROOT/ios && pod install; popd