Feature Request: Ability To Set Sleep Timer To Any Amount Of Time

### What problem does this address?

The sleep timer arbitrarily won't work for anything below 5 minutes and only works for multiplies of 5 minutes and you can't set seconds.

### What is your proposed solution?

Keep quick time shortcuts but let people set more specific timers for any time and not just multiples of 5 minutes.

### Did you search for existing feature suggestions?

- [X] I have searched for existing feature suggestions.

The issue does not name a file or test. Start by locating the existing sleep-timer implementation and its quick-time shortcuts, then trace how timer values are selected and applied. Done means users can retain the shortcuts while setting any duration, including values below five minutes and durations with seconds.

Written by the indexing model from the issue text.