REGEX-Escape for: HEADER_SEARCH_PATHS = "$(SRCROOT)/../node_modules/react-native-navigation/ios/**";

Your Input:
Result, the escaped string:
HEADER_SEARCH_PATHS \= "\$\(SRCROOT\)\/\.\.\/node_modules\/react\-native\-navigation\/ios\/\*\*";

What must the escaping look like for:
HEADER_SEARCH_PATHS = "$(SRCROOT)/../node_modules/react-native-navigation/ios/**";

The excaped text for use in a regex is:
HEADER_SEARCH_PATHS \= "\$\(SRCROOT\)\/\.\.\/node_modules\/react\-native\-navigation\/ios\/\*\*";