[To-Do FAQ] Add an FAQ for the ValueError in GTN

This issue is a part of a PR: #3421

_Need to create a distinct FAQ category for ValueError job failure (an exact keyword match for the error metadata)_
Mentioning @jennaj to have a look at this.

Review PR #3421 and the existing FAQ structure to find where ValueError job failures are categorized. Confirm the error metadata keyword matching approach, then add the distinct ValueError FAQ category and verify that its wording and exact keyword match are represented correctly.

Written by the indexing model from the issue text.