and add command to task building progress

Fixes #81636

fixes #71407

Also changes processService to not modify its input actions, which seems like unexpected behavior

These arrays of actions should not be modified by the caller. Mark them as readonly to prevent this. This also let me eliminate a number of not null supressions that had been introduced during the strict null migration

One small code change was required in `showError`. However I believe this was actually a bug since modifying the input array was likely not what would be expected (in practice, we usually just passed in array literals so I don't think we hit this one)

This state is currently unused and make no sense. Update the signature to  prevent ever trying to go into this state

**Problem**
In progress service, the `ProgressState` object is quite difficult to understand. Only a subset of fields are active at a given time so the state is really more like a state machine.

When enabling strict null checks, the existing pattern is also a pain because it is not clear which subset of fields go to gether and will not be undefined

**Fix**
I've been experimenting with writing states much explicitly. This has two main points:

- Encapsulating all state in a single state object (which the progress service already does)
- Encoding each valid state very explicitly in a state machine like manner

For progress service, the encoding breaks the `ProgressState` object up into five different states that the progress service transitions between.

These values are really supposed to be undefined