Improve pre-selection visibility

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Problem description

On a high resolution display pre-selection of lines and vertices is very difficult to see. There doesn’t seem to be a single choice of pre-selection colour that works well for all objects.

Could we perhaps use a high contrast / reverse video effect for pre-selection rather than a single nominated colour? It would also be helpful if we could add some kind of bloom, or enlargement of preselected objects to make them stand out.

### Full version info

```shell
v0.21 and v0.22 weekly build. Will update with full info later.
```

### Subproject(s) affected?

None

### Anything else?

_No response_

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct