Un-deprecate async useComputed$

[wmertens]

Now that #7552 landed, we don't need deprecation any more.

However, we should add an eslint rule that checks when you use an AUC result synchronously, because that will always result in a restart of the running context.

[shairez]

@wmertens we discussed in today's meeting with @Varixo and the rest of the participants the need to revert back #7552.

Basically there are two options:

1. We revert that PR to prevent footguns (because the fix you thought fixed this in feat: allow async operations in useComputed$ hook #7552 turned out to be just partially fixing it)
   and we introduce useAsyncComputed$ with a track function that returns a signal (unlike useTask which doesn't)

2. Adding a lint rule as you suggested in here and adding a track function to the existing implementation.

I tend to go with option 1 because it makes things more explicit and less relying on linting rules (like you cannot go wrong when using useComputed$ because typescript will stop you first.
But I see the value in keeping both concepts in the same hook.

This is not a trivial one, @mhevery would love to also get your opinion on this

[Varixo]

Related: #7561