Should be able to cancel a `Waiting` resource's startup

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Is your feature request related to a problem? Please describe the problem.

If a resource is in the `Waiting state, I should be able to cancel the resource start to stop it form running once it's dependencies are avaialble. Take the `blockee` resoruce below
```
var blocker = builder.AddExecutable("blocker", "pwsh", ".")
.WithExplicitStart();
var blockee = builder.AddExecutable("blockee", "pwsh", ".")
.WaitFor(blocker);
```

### Describe the solution you'd like

The `Stop` command should be available, and would cancel the wait and abort the process from starting up any further.

### Additional context

Some relation to to #14812