bug(developer): Unable to remove all other keyboards from the keyboard dropdown list when testing a keyboard in a local browser

### Describe the bug

In the process of testing a keyboard in a local browser using Keyman Developer, it is not possible to eliminate all other keyboards from the keyboard dropdown list.

### Reproduce the bug

1. Install Keyman Developer 17.0.193-alpha build.
2. Open a Keyboard project. (eg., gff_amharic.kpj)
3. Click the build tab.
4. Click the "Test Keyboard on web" button from the 'Web and Mobile Targets' pane.
5. Click the 'http://localhost:8008' web address.
6. Click the 'Open in browser' button.

We may notice that the localhots:8008 browser opens.

7. Click the 'Keyboard' drop-down list.

Here, I noticed that there are (already added) more keyboards appearing in the list. So, it is confusing to search for the newly added keyboard. It would be better to remove the already added keyboards. Seems to be an issue.

### Expected behavior

It should be possible to remove the older or existing keyboards from the Keyboard dropdown list.

### Related issues

_No response_

### Keyman apps

- [ ] Keyman for Android
- [ ] 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

17.0.193-alpha

### Operating system

Windows 10 OS, Windows 11 OS (VM)

### Device

_No response_

### Target application

_No response_

### Browser

_No response_

### Keyboard name

_No response_

### Keyboard version

_No response_

### Language name

_No response_

### Additional context

_No response_