No entry field for icon-padding

[zstadler]

Maputnik version: v2.1.1 - web page
Browser: Firefox 128.3.1esr, Chrome 130.0.6723.70
OS: Win 11 Pro

Description of the bug:
There is no entry field for icon-padding property of symbol layers.

Steps to reproduce the behavior:

1. Create a new symbol layer or select a symbol layer of an existing style
2. Expand "Icon layout properties", if needed
3. Attempt to enter a value for padding

Style file or style URL:
N/A

Screenshots:

[HarelM]

This is probably because of the "special" type that padding was modified to - both array and a number... :-/