Resolves the `// TODO Fix eslint` left on the TTL validation. `ttlVal` is
always a number (`NaN` or a `Math.trunc` result), so `Number.isFinite` is
equivalent to the global `isFinite` here while satisfying
`unicorn/prefer-number-properties`, letting us drop the accompanying
`eslint-disable-next-line`.
Signed-off-by: DL6ER <dl6er@dl6er.de>