Fix accurateCastOrNull/accurateCastOrDefault from String to JSON

[Avogar]

Changelog category (leave one):

• Bug Fix (user-visible misbehavior in an official stable release)

Changelog entry (a user-readable short description of the changes that goes into CHANGELOG.md):

Fix accurateCastOrNull/accurateCastOrDefault from String to JSON.

Closes #85226

Documentation entry for user-facing changes

• Documentation is written (mandatory for new features)

[clickhouse-gh]

Workflow [PR], commit [72f91db]

Summary: ❌

job_name	test_name	status	info	comment
Stateless tests (amd_ubsan, parallel)		failure
	00906_low_cardinality_cache	FAIL

[Avogar]

Stateless tests (amd_ubsan, parallel) - test 00906_low_cardinality_cache fails with Estimated query execution time (627.30974 seconds) is too long. Maximum: 600. It's quite rare for this test (only 2 such falilures for last 90 days), so I won't create an issue for it for now.