`prefer-message-ids` rule should not flag missing `meta.messages` when `context.markVariableAsUsed()` is present

[bmish]

It turns out that a rule can be valid even if it never reports a violation and thus has no messages.

Example: https://github.com/jsx-eslint/eslint-plugin-react/blob/8306a7bc81be567d36c02e21c1d68f44fa3468e3/lib/rules/jsx-uses-vars.js#L54