Restart task is not triggered from command and top level menu

[michelkaporin]

Testing #29618.

1. Clone https://github.com/Microsoft/vscode-languageserver-node and do npm install's
2. Run the following task task tsc: build client\src\tsconfig.json through Task menu
3. Once terminated, do 'Task -> Restart Task...' from menu.
   Observe that nothing happens.

Same happens if restart task is triggered from command palette. I assume this is because we moved tasks to a terminal by default.

[michelkaporin]

It's interesting if I do the same but in jsonrpc subfolder, then 'Restart Task' works as a charm.

[dbaeumer]

@michaelchiche restart task terminates a running task and restarts it. I will add a message to say that no task is running if a user triggers the action. I will also rename it to Restart Running Task...