Allow react-native and expo to build when using GNU coreutils

See the issue at #32432 (comment)

This fixes a bizarre issue when using the GNU coreutils tools. There are very minor changes in the standard command-line tools on macOS and the GNU coreutils. The `cp` command has slightly different semantics across these operating systems, so this commit normalizes those differences and allows GNU coreutils to be used or the system native version of `cp`.

scripts/react_native_pods_utils/script_phases.sh

@@ -108,7 +108,7 @@ moveOutputs () {
     mkdir -p "$RCT_SCRIPT_OUTPUT_DIR"
 
     # Copy all output to output_dir
-    cp -R "$TEMP_OUTPUT_DIR/" "$RCT_SCRIPT_OUTPUT_DIR" || exit 1
+    cp -R "$TEMP_OUTPUT_DIR/." "$RCT_SCRIPT_OUTPUT_DIR/." || exit 1
     echo "$LIBRARY_NAME output has been written to $RCT_SCRIPT_OUTPUT_DIR:" >> "${SCRIPT_OUTPUT_FILE_0}" 2>&1
     ls -1 "$RCT_SCRIPT_OUTPUT_DIR" >> "${SCRIPT_OUTPUT_FILE_0}" 2>&1
 }