message: cli: make diff handler remove deps
diff: @@ -168,6 +168,10 @@ class PackageJsonHandler {
  return;
  }
  + // Hardcoded removal of these during migration
  + await this.syncField('@backstage/core', {}, targetDeps, fieldName);
  + await this.syncField('@backstage/core-api', {}, targetDeps, fieldName);
  +
  for (const key of Object.keys(pkgDeps)) {
  if (this.variant === 'app' && key.startsWith('plugin-')) {
  continue;
  