bug(windows): Installing keyboard over network drive fails

### Describe the bug

When you try to install a keyboard that is located on a network drive, it goes through the process of "installing", but it doesn't show up. Marc said a solution would probably be to copy first to the temp directory, and then give the elevated process that location to copy from.

### Reproduce the bug

_No response_

### Expected behavior

You should be able to install keyboards located on a network drive.

### Related issues

_No response_

### Keyman apps

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

### Keyman version

16

### Operating system

Windows 11

### Device

Windows desktop

### Target application

_No response_

### Browser

_No response_

### Keyboard name

_No response_

### Keyboard version

_No response_

### Language name

_No response_

### Additional context

_No response_