Fix to compile under standard clang16: static_assert in template in ydb/core/tx/replication/service/json_change_record.cpp

[alexv-smirnov]

When compiling using a standard clang-16, this template fails to compile with the following error:

ydb/core/tx/replication/service/json_change_record.cpp:88:9: error: static assertion failed: Unsupported type
        static_assert(false, "Unsupported type");

Refactored to two separate functions without using template to avoid this error.

[github-actions]

🟢 2025-11-04 11:18:27 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-11-04 11:18:41 UTC Pre-commit check linux-x86_64-release-asan for 1929c95 has started.
⚪ 2025-11-04 11:18:57 UTC Artifacts will be uploaded here
⚪ 2025-11-04 11:20:18 UTC ya make is running...
🟡 2025-11-04 13:12:15 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
15326	14908	0	198	197	23

🟢 2025-11-04 13:12:22 UTC Build successful.
🟢 2025-11-04 13:12:44 UTC ydbd size 3.8 GiB changed* by -240 Bytes, which is <= 0 Bytes vs main: OK

ydbd size dash	main: 802fb8a	merge: 1929c95	diff	diff %
ydbd size	4 068 675 512 Bytes	4 068 675 272 Bytes	-240 Bytes	-0.000%
ydbd stripped size	1 510 375 912 Bytes	1 510 375 848 Bytes	-64 Bytes	-0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

⚪ 2025-11-04 11:18:48 UTC Pre-commit check linux-x86_64-relwithdebinfo for 1929c95 has started.
⚪ 2025-11-04 11:19:04 UTC Artifacts will be uploaded here
⚪ 2025-11-04 11:20:30 UTC ya make is running...
🟡 2025-11-04 12:47:31 UTC Some tests failed, follow the links below. Going to retry failed tests...

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
31455	30036	0	2	1388	29

⚪ 2025-11-04 12:48:08 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-11-04 12:55:01 UTC Tests successful.

Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
57 (only retried tests)	42	0	0	0	15

🟢 2025-11-04 12:55:08 UTC Build successful.
🟢 2025-11-04 12:55:23 UTC ydbd size 2.3 GiB changed* by -160 Bytes, which is <= 0 Bytes vs main: OK

ydbd size dash	main: 802fb8a	merge: 1929c95	diff	diff %
ydbd size	2 429 287 080 Bytes	2 429 286 920 Bytes	-160 Bytes	-0.000%
ydbd stripped size	516 135 944 Bytes	516 135 944 Bytes	0 Bytes	0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}