option to edit cmdpal dock extension/app icon when adding/editing dock (context menu)

### Description of the new feature / enhancement

Option to edit cmdpal dock extension/app icon when adding/editing dock (context menu)

### Scenario when this would be used?

when adding/editing dock (context menu)

### Supporting information

like changing the icon into any segoe fluent icons or any .ico/.png

Start by locating the cmdpal dock add/edit context-menu entry point and the code that supplies extension or app icons. Determine how Segoe Fluent icons and .ico/.png files are currently represented, then define the supported editing flow and verify that a selected custom icon appears when the dock item is added or edited.

Written by the indexing model from the issue text.