Tests: isolate plugin project modules

vitest.plugins.config.ts

@@ -4,6 +4,7 @@ export function createPluginsVitestConfig(env?: Record<string, string | undefine
   return createScopedVitestConfig(["src/plugins/**/*.test.ts"], {
     dir: "src/plugins",
     env,
+    isolate: true,
     name: "plugins",
     passWithNoTests: true,
   });