mouse-cursor color in text box in Light Theme

### Feature Idea

In text boxes in the GUI, for example "CLIP Text Encode":
- in Dark Theme: the mouse cursor is white, nicely contrasting with the dark background, easy to see.
- in Light Theme: the mouse cursor is grey, virtually impossible to see against the grey background.
(this is about the mouse cursor, the on-screen pointer controlled by the physical mouse)
(not about the keyboard cursor, the blinking vertical line indicating where text will appear)

The keyboard cursor in Light Theme is a black cursor. Easy to see.
Can the mouse cursor also be made black in Light Theme when inside a text box?

### Existing Solutions

I could not immediately find any.

### Other

_No response_

No file, test, or entry point is named in the issue. Begin by locating the GUI text-box styling and reproduce the pointer in both themes; done means the mouse pointer is clearly visible inside text boxes in Light Theme without changing the keyboard cursor.

Written by the indexing model from the issue text.