chore(test): remove NO_COLOR workaround for Rstest

Rstest no longer injects FORCE_COLOR into test workers since @rstest/core 0.12.2, so the test config no longer needs to disable colors.

Author: fi3ework

packages/rstack/rstack.config.ts

@@ -3,9 +3,6 @@ import { withRslibConfig } from '@rstest/adapter-rslib';
 import { define } from 'rstack';
 
 define.test(() => {
-  // Disable color in test
-  process.env.NO_COLOR = '1';
-
   return {
     // Temporary projects may contain files that match Rstest's test glob.
     exclude: ['**/test-temp-*/**'],