This is much simpler than the matching task for statement guids described in T226216 as the "hash" key is only used for a single reason in our JSON output, for snak hashes.
Thus, removing hashes from the AF text should be as simple as adding "hash" to the arrays in the getIgnoreKeysForFilters method for items and properties in the ItemContent and PropertyContent classes.
This is technically a breaking change, so this should be announced.