Fix some vars from preconfiguration not being added to package polici…

…es (elastic#113204) (elastic#113251)

Co-authored-by: Jen Huang <[email protected]>

x-pack/plugins/fleet/server/services/package_policy.ts

@@ -1014,7 +1014,7 @@ function deepMergeVars(original: any, override: any): any {
 
   for (const { name, ...overrideVal } of overrideVars) {
     const originalVar = original.vars[name];
-    result.vars[name] = { ...overrideVal, ...originalVar };
+    result.vars[name] = { ...originalVar, ...overrideVal };
   }
 
   return result;