Merge pull request storybookjs#10917 from storybookjs/fix/10519

UI: Fix search in production mode

lib/core/src/client/preview/loadCsf.ts

@@ -40,7 +40,7 @@ const loadStories = (
             fileExports,
             // todo discuss: types infer that this is RequireContext; no checks needed?
             // NOTE: turns out `babel-plugin-require-context-hook` doesn't implement this (yet)
-            typeof req.resolve === 'function' ? req.resolve(filename) : null
+            typeof req.resolve === 'function' ? req.resolve(filename) : filename
           );
         } catch (error) {
           logger.warn(`Unexpected error: ${error}`);