vscode.tasks.executeTask(task) does not run dependencies

[tsmaeder]

I cannot really test this because of #7514, but from my reading of the code, the VS Code API call 'executeTask` goes more or less directly to

theia/packages/task/src/browser/task-service.ts

Line 691 in 2ccfa67

async runTask(task: TaskConfiguration, option?: RunTaskOption): Promise<TaskInfo | undefined> {

This code path does not seem to consider dependent tasks at all. VS Code does.