[clarity] All check errors must be handled as runtime errors

[jcnelson]

Right now, (at-block) can emit CheckErrors which cause the transaction to be invalid, as well as the block that includes it. In Stacks 2.1, we should make it so that any error emitted by (at-block) is a RuntimeError, so at least the transaction will be mineable and fees will be collected.

[jcnelson]

N.B. this applies to all check errors. We should not merely re-cast all check errors as runtime errors, but instead treat check errors the way we do for runtime errors -- i.e. they don't invalidate the block; they only debit the sender the tx fee (but the tx receipt should contain the original check error).

[saralab]

A good one for @obycode to help with.

[obycode]

👍 I just finished reviewing the PR.

[jcnelson]

I already did this one @saralab.

Thank you for your review @obycode!