test(nuxt): Make Nuxt 5 (nightly) E2E optional (#20113)

Nuxt 5 is still in development and currently in a nightly version. The
E2E tests might fail due to changes but this should not block CI as long
as v5 is in nightly.

This adds the `optional` label to the test.

E.g. unblocking this PR:
#20071

Author: s1gr1d

dev-packages/e2e-tests/test-applications/nuxt-5/package.json

@@ -31,6 +31,9 @@
     "@playwright/test": "~1.56.0",
     "@sentry-internal/test-utils": "link:../../../test-utils"
   },
+  "sentryTest": {
+    "optional": true
+  },
   "volta": {
     "extends": "../../package.json",
     "node": "22.20.0"