Bump vitest from 2.1.4 to 2.1.9 (#3039)

Author: dependabot[bot]

packages/typespec-python/package.json

@@ -81,7 +81,7 @@
     "@types/yargs": "~17.0.33",
     "@types/semver": "7.5.8",
     "c8": "^10.1.2",
-    "vitest": "^2.1.2",
+    "vitest": "^2.1.9",
     "rimraf": "~6.0.1",
     "typescript": "~5.6.3",
     "typescript-eslint": "^8.8.1",