Fix output path for generated artifacts

Summary:
This is a fix for facebook#45112
This diff changes the codegen so that the output path is computed relative to project root (or `path` if provided) instead of current working directory.

Changelog: [General][Fixed] - Codegen computes output path relative to project root instead of current working directory.

Reviewed By: fkgozali

Differential Revision: D59009821

packages/react-native/scripts/codegen/generate-artifacts-executor.js

@@ -365,7 +365,7 @@ function computeOutputPath(projectRoot, baseOutputPath, pkgJson, platform) {
   if (baseOutputPath == null) {
     const outputDirFromPkgJson = readOutputDirFromPkgJson(pkgJson, platform);
     if (outputDirFromPkgJson != null) {
-      baseOutputPath = outputDirFromPkgJson;
+      baseOutputPath = path.join(projectRoot, outputDirFromPkgJson);
     } else {
       baseOutputPath = projectRoot;
     }