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 11:25:54 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-09-05 11:27:12 UTC Pre-commit check linux-x86_64-relwithdebinfo for d481b7f has started.
⚪ 2025-09-05 11:27:27 UTC Artifacts will be uploaded here
⚪ 2025-09-05 11:30:30 UTC ya make is running...
🟡 2025-09-05 12:37:12 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?
28605	27316	0	6	1225	58

⚪ 2025-09-05 12:39:49 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-09-05 13:01:54 UTC Tests successful.

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

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
102 (only retried tests)	59	0	0	2	41

🟢 2025-09-05 13:02:02 UTC Build successful.
🟢 2025-09-05 13:02:19 UTC ydbd size 2.2 GiB changed* by +4.2 KiB, which is < 100.0 KiB vs stable-25-1-4: OK

ydbd size dash	stable-25-1-4: dd5ae19	merge: d481b7f	diff	diff %
ydbd size	2 323 270 672 Bytes	2 323 274 992 Bytes	+4.2 KiB	+0.000%
ydbd stripped size	487 033 536 Bytes	487 034 368 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 11:31:46 UTC Pre-commit check linux-x86_64-release-asan for d481b7f has started.
⚪ 2025-09-05 11:31:50 UTC Artifacts will be uploaded here
⚪ 2025-09-05 11:34:44 UTC ya make is running...
🟡 2025-09-05 12:55:42 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?
14431	14212	0	60	121	38

⚪ 2025-09-05 12:56:55 UTC ya make is running... (failed tests rerun, try 2)
🟡 2025-09-05 13:18:17 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?
259 (only retried tests)	200	0	2	22	35

⚪ 2025-09-05 13:18:27 UTC ya make is running... (failed tests rerun, try 3)
🟡 2025-09-05 13:38:46 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?
85 (only retried tests)	33	0	2	17	33

🟢 2025-09-05 13:38:54 UTC Build successful.
🟢 2025-09-05 13:39:17 UTC ydbd size 3.8 GiB changed* by +8.4 KiB, which is < 100.0 KiB vs stable-25-1-4: OK

ydbd size dash	stable-25-1-4: dd5ae19	merge: d481b7f	diff	diff %
ydbd size	4 042 779 840 Bytes	4 042 788 392 Bytes	+8.4 KiB	+0.000%
ydbd stripped size	1 407 489 240 Bytes	1 407 492 248 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}