Client/Michelson/Error reporting: ignore the script part of runtime errors

Context

Client fix for the regression introduced by !4181 (merged).

Manually testing the MR

There are two execution paths tested in the CI:

• using tezos-client run script on a failed script (for example tezos-client run script 'parameter unit; storage unit; code FAILWITH on storage Unit and input Unit`)
• using tezos-client transfer on a failed script (for example ŧezos-client originate contract saucisse transferring 0 from bootstrap1 running 'parameter unit; storage unit; code FAILWITH' --burn-cap 1; tezos-client transfer 0 from bootstrap1 to saucisse)

Checklist

• Document the interface of any function added or modified (see the coding guidelines)
• Document any change to the user interface, including configuration parameters (see node configuration)
• Provide automatic testing (see the testing guide).
• For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, the Development Version section of CHANGES.md for everything else).
• Select suitable reviewers using the Reviewers field below.
• Select as Assignee the next person who should take action on that MR