Prevent automatic sliding of datetime when chaning the opposite field

**Describe the bug** When setting a new datetime, either for a manual tracker or adjusting an existing entry, which will put "start" and "end" in contradiction, i.e. when "end" is before "start", the unselected time will be set to a 15 minutes offset with the correct flow. I'm sure this is a feature, however I'm reporting it as a bug since it can cause confusion and/or losing one of the times when trying to manually adjust an entry, specially when adjusting midnight times or adjusting `end` before `start`. **To Reproduce** Steps to reproduce the behavior: 1. Select manual tracker or use an existing entry. 2. Entry has `start` and `end` just past midnight, e.g. 2026/02/27 00:30 and 1:00 3. Click on `start` and adjust the time intending to set it up the day before, e.g. 23:50 4. **The `end` time has now jumped to 2026/02/28 00:05 without notice** (with an intermediate step of 23:45 since 30 minutes was set when the hour 23 was selected) 5. Click on calendar and adjust date to a day before, e.g. 2026/02/26 6. **Click on `end` and realize it had been modified.** **Expected behavior** Allow user to set up `start` and `end` independently and show user error of inconsistencies instead of silently adjusting other fields. **Screenshots** **Additional context**