task created from task definition contributed from VS Code extension throws exception

[jcortell68]

Bug Description:

I've been playing around with creating a custom task definition in a VS Code extension I got a very primitive example working in VS Code. When I tried the same VS Code extension in Theia, I get an exception when I invoke the task.

2023-07-18T13:22:16.497Z root ERROR Request run failed with error: Process task config must have 'command' property specified Error: Process task config must have 'command' property specified
    at ProcessTaskRunner.run (C:\j.cortell\git\theiasandbox\node_modules\@theia\task\lib\node\process\process-task-runner.js:51:19)
    at TaskServerImpl.run (C:\j.cortell\git\theiasandbox\node_modules\@theia\task\lib\node\task-server.js:75:35)
    at RpcProxyFactory.onRequest (C:\j.cortell\git\theiasandbox\node_modules\@theia\core\lib\common\messaging\proxy-factory.js:134:49)
    at RpcProtocol.requestHandler (C:\j.cortell\git\theiasandbox\node_modules\@theia\core\lib\common\messaging\proxy-factory.js:115:80)
    at RpcProtocol.handleRequest (C:\j.cortell\git\theiasandbox\node_modules\@theia\core\lib\common\message-rpc\rpc-protocol.js:171:39)
    at RpcProtocol.handleMessage (C:\j.cortell\git\theiasandbox\node_modules\@theia\core\lib\common\message-rpc\rpc-protocol.js:68:26)
    at C:\j.cortell\git\theiasandbox\node_modules\@theia\core\lib\common\message-rpc\rpc-protocol.js:51:66
    at C:\j.cortell\git\theiasandbox\node_modules\@theia\core\lib\common\event.js:103:69
    at CallbackList.invoke (C:\j.cortell\git\theiasandbox\node_modules\@theia\core\lib\common\event.js:109:26)
    at Emitter.fire (C:\j.cortell\git\theiasandbox\node_modules\@theia\core\lib\common\event.js:224:29)
2023-07-18T13:22:16.503Z task ERROR Error launching task 'mytasktype: my source': Process task config must have 'command' property specified

I thought this issue might be specific to using a vscode.CustomExection in the contributed implementation of the task, but it happens equally if I use vscode.ShellExecution

Steps to Reproduce:

git clone -b task_definitions_bug1 https://github.com/jcortell68/theiasandbox
cd theiasandbox
yarn
yarn start:electron

Additional Information

• Operating System: Windows
• Theia Version: 1.39