fix neighbours count (#6409)

[vporyadke]

Changelog entry

fix a bug where a tablet was considered its own "neighbour", which made the current node always less favorable and could lead to unnecessary tablet moves

Changelog category

• Bugfix

Additional information

Backport of #6409

[github-actions]

⚪ 2024-07-16 07:38:13 UTC Pre-commit check for 1abb838 has started.
⚪ 2024-07-16 07:40:40 UTC Build linux-x86_64-relwithdebinfo is running...
🟢 2024-07-16 08:18:02 UTC Build successful.
⚪ 2024-07-16 08:18:18 UTC Tests are running...
🔴 2024-07-16 09:39:25 UTC Some tests failed, follow the links below.

Test history | Test log

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
14090	12771	0	1	1306	12

🟢 2024-07-16 09:40:11 UTC ydbd size 8.1 GiB changed* by +176 Bytes, which is < 100.0 KiB vs stable-24-3: OK

ydbd size dash	stable-24-3: 14c79b8	merge: 1abb838	diff	diff %
ydbd size	8 727 365 536 Bytes	8 727 365 712 Bytes	+176 Bytes	+0.000%
ydbd stripped size	477 191 496 Bytes	477 191 560 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]

⚪ 2024-07-16 07:39:14 UTC Pre-commit check for 1abb838 has started.
⚪ 2024-07-16 07:41:41 UTC Build linux-x86_64-release-clang14 is running...
🟢 2024-07-16 08:00:36 UTC Build successful.

[github-actions]

⚪ 2024-07-16 07:39:57 UTC Pre-commit check for 1abb838 has started.
⚪ 2024-07-16 07:42:31 UTC Build linux-x86_64-release-asan is running...
🟢 2024-07-16 08:05:39 UTC Build successful.
⚪ 2024-07-16 08:05:55 UTC Tests are running...
🔴 2024-07-16 10:04:39 UTC Some tests failed, follow the links below.

Test history | Test log

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
9817	9248	0	82	316	171

🟢 2024-07-16 10:05:27 UTC ydbd size 5.2 GiB changed* by +16 Bytes, which is < 100.0 KiB vs stable-24-3: OK

ydbd size dash	stable-24-3: 14c79b8	merge: 1abb838	diff	diff %
ydbd size	5 616 609 688 Bytes	5 616 609 704 Bytes	+16 Bytes	+0.000%
ydbd stripped size	1 211 261 800 Bytes	1 211 261 800 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}