feat(developer): Support "width" and "padding" attributes in Longpress Keys

### Is your feature request related to a problem? Please describe.

When many longpress keys appear in a popup list, it can take a few moments to find the desired key. Color coding the longpress keys is helpful, additionally, it would be helpful to better distinguish some keys in the list if the space between them could be increased.

### Describe the solution you'd like

The `Width` and `Padding Left` features available for regular keys, should also be available for the longpress keys.

### Describe alternatives you've considered

Sobbing alone in a dark room 😭

### Related issues

_No response_

### Keyman apps

- [X] Keyman for Android
- [X] Keyman for iPhone and iPad
- [ ] Keyman for Linux
- [ ] Keyman for macOS
- [ ] Keyman for Windows
- [X] Keyman Developer
- [ ] KeymanWeb
- [ ] Other - give details at bottom of form

### Keyman version

16.0.139

### Operating system

Windows 11

### Device

laptop

### Target application

_No response_

### Browser

_No response_

### Keyboard name

Any

### Keyboard version

Any

### Language name

Any

### Additional context

_No response_