Make `dehumanize()` handle values with decimal fractions correctly

## Feature Request
Currently, `dehumanize()` is not capable of correctly parsing values with a floating point.
```py
>>> arrow.get("2025-12-10T09:00:00").dehumanize("2 days 3.5 hours ago")

```
It seems that parser pretty much ignores the part up to the floating point.

A more expected result, however, would be that resulting Arrow object is ``

Not sure if there is a need to make floating point locale-dependent (ie, `.` or `,`), perhaps it'd be fine to allow both.