[vscode] Issue when running extensions with TestControllers

[rschnekenbu]

In current Theia Master, I get some error messages in the console when activating an extension that uses the TestController and TestRunProfile APIs.
I use the test-provider-sample of the vscode-extension-sample repository:
-src: test-provider-sample-0.0.1-src.zip

• vsix zip: test-provider-sample-0.0.1.zip

I get the following logs with this extension, when switching to the Testing panel:

2024-06-13T08:25:00.727Z root ERROR Error: No test controller with id mathTestController found
    at TestingMainImpl.$notifyTestRunProfileCreated (http://localhost:3000/packages_plugin-ext_lib_hosted_browser_hosted-plugin_js.js:11513:19)
    at RpcInvocationHandler.onNotification (http://localhost:3000/packages_plugin-ext_lib_common_plugin-api-rpc_js-packages_plugin-ext_lib_main_browser_hierarc-ea2111.js:852:28)
    at http://localhost:3000/packages_plugin-ext_lib_common_plugin-api-rpc_js-packages_plugin-ext_lib_main_browser_hierarc-ea2111.js:845:43
    at http://localhost:3000/bundle.js:343876:69
    at CallbackList.invoke (http://localhost:3000/bundle.js:343882:26)
    at Emitter.fire (http://localhost:3000/bundle.js:343997:36)
    at RpcProtocol.handleNotify (http://localhost:3000/bundle.js:347824:36)
    at RpcProtocol.handleMessage (http://localhost:3000/bundle.js:347694:26)
    at http://localhost:3000/bundle.js:347676:66
    at http://localhost:3000/bundle.js:343876:69

That works well on VS Code.
Next step of investigation is to check the order in which the notifications are send / received / process on the 2 sides. Goal is to check if there is any issue there or if something else is happening.