bug(developer): EAssertionFailed: Exception EAssertionFailed in module Tike.exe at 007E3B16.

Sentry Issue: [KEYMAN-DEVELOPER-FT](https://sentry.io/organizations/keyman/issues/3446919261/?project=5983519)

```
EAssertionFailed: Exception EAssertionFailed in module Tike.exe at 007E3B16.
TAppSourceHttpResponder.RegisterSource was called for a file that is already registered: C:\Projects\keyman\app\windows\src\test\unit-tests\kmcomp\test_touchlayout_14_2.keyman-touch-layout (C:\projects\keyman\app\windows\src\developer\tike\http\Keyman.Developer.System.HttpServer.AppSource.pas, line 307).

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(26 additional frame(s) were not displayed)
```

This issue arises if you attempt to open two keyboard source files that both reference the same touch layout file.

Furthermore, if you open the first file, and in the layout file change the file reference, this does not appear to release the link to the file.