Fixed processing kafka batch v0 with many messages

[nshestakov]

Changelog entry

Поправлена ошибка, когда при записи сообщений kafka , использующих формат батча v0 и v1 сохранялось только первое сообщение батча (все остальные игнорировались)

Changelog category

• Bugfix

Description for reviewers

LOGBROKER-9936
#24272

[github-actions]

🟢 2025-09-05 11:28:32 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-09-05 11:29:30 UTC Pre-commit check linux-x86_64-relwithdebinfo for ea93eec has started.
⚪ 2025-09-05 11:31:00 UTC Artifacts will be uploaded here
⚪ 2025-09-05 11:34:24 UTC ya make is running...
🟡 2025-09-05 12:24:43 UTC Some tests failed, follow the links below. Going to retry failed tests...

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
28616	27330	0	4	1239	43

⚪ 2025-09-05 12:27:25 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-09-05 12:54:48 UTC Tests successful.

Test history | Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
100 (only retried tests)	62	0	0	2	36

🟢 2025-09-05 12:54:55 UTC Build successful.
🟢 2025-09-05 12:55:11 UTC ydbd size 2.2 GiB changed* by +4.2 KiB, which is < 100.0 KiB vs stable-25-2: OK

ydbd size dash	stable-25-2: 37df881	merge: ea93eec	diff	diff %
ydbd size	2 324 647 336 Bytes	2 324 651 640 Bytes	+4.2 KiB	+0.000%
ydbd stripped size	487 220 392 Bytes	487 221 224 Bytes	+832 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]

⚪ 2025-09-05 11:36:06 UTC Pre-commit check linux-x86_64-release-asan for ea93eec has started.
⚪ 2025-09-05 11:36:35 UTC Artifacts will be uploaded here
⚪ 2025-09-05 11:39:57 UTC ya make is running...
🟡 2025-09-05 12:47:23 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet Going to retry failed tests...

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
14433	14232	0	43	123	35

⚪ 2025-09-05 12:48:44 UTC ya make is running... (failed tests rerun, try 2)
🟡 2025-09-05 13:00:57 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet Going to retry failed tests...

Test history | Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
243 (only retried tests)	190	0	2	21	30

⚪ 2025-09-05 13:01:09 UTC ya make is running... (failed tests rerun, try 3)
🟡 2025-09-05 13:13:38 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Test history | Ya make output | Test bloat | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
78 (only retried tests)	32	0	2	15	29

🟢 2025-09-05 13:13:45 UTC Build successful.
🟢 2025-09-05 13:14:07 UTC ydbd size 3.8 GiB changed* by +8.3 KiB, which is < 100.0 KiB vs stable-25-2: OK

ydbd size dash	stable-25-2: 37df881	merge: ea93eec	diff	diff %
ydbd size	4 045 402 528 Bytes	4 045 411 024 Bytes	+8.3 KiB	+0.000%
ydbd stripped size	1 408 431 352 Bytes	1 408 434 296 Bytes	+2.9 KiB	+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}