Fix incorrect PDisk ColorBorder setting

[rosik]

Changelog category

• Not for changelog (changelog entry is not required)

Description for reviewers

• Fix-up for Add PDiskControls.SemiStrictSpaceIsolation to ICB #26038

It only affected ICB SemiStrictSpaceIsolation option. After enabling it, the BorderOccupancy was calculated incorrectly (too small). The bug revealed in #28314

[Copilot]

Pull Request Overview

This PR refactors the color occupancy calculation logic in the PDisk chunk tracker by introducing a new convenience method in TPerOwnerQuotaTracker and adding const qualifiers to improve code clarity and maintainability.

• Added GetOccupancyForColor method to TPerOwnerQuotaTracker to encapsulate color occupancy calculation
• Made ColorFlagLimit method const-qualified
• Replaced direct ColorLimits.GetOccupancyForColor calls with the new wrapper method

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[github-actions]

🟢 2025-11-07 13:48:17 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-11-05 15:12:27 UTC Pre-commit check linux-x86_64-relwithdebinfo for f9a72df has started.
⚪ 2025-11-05 15:12:43 UTC Artifacts will be uploaded here
⚪ 2025-11-05 15:14:08 UTC ya make is running...
🟡 2025-11-05 17:15:04 UTC Some tests failed, follow the links below. Going to retry failed tests...

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
39810	36974	0	3	2803	30

⚪ 2025-11-05 17:15:19 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-11-05 17:25:52 UTC Tests successful.

Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
76 (only retried tests)	62	0	0	0	14

🟢 2025-11-05 17:25:54 UTC Build successful.
🟢 2025-11-05 17:26:11 UTC ydbd size 2.3 GiB changed* by -112 Bytes, which is <= 0 Bytes vs main: OK

ydbd size dash	main: d793be5	merge: f9a72df	diff	diff %
ydbd size	2 429 698 736 Bytes	2 429 698 624 Bytes	-112 Bytes	-0.000%
ydbd stripped size	516 203 144 Bytes	516 203 144 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}

[github-actions]

⚪ 2025-11-05 15:12:27 UTC Pre-commit check linux-x86_64-release-asan for f9a72df has started.
⚪ 2025-11-05 15:12:45 UTC Artifacts will be uploaded here
⚪ 2025-11-05 15:14:09 UTC ya make is running...
🟡 2025-11-05 17:46:21 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?
16217	15815	0	159	215	28

🟢 2025-11-05 17:46:27 UTC Build successful.
🟢 2025-11-05 17:46:50 UTC ydbd size 3.8 GiB changed* by -712 Bytes, which is <= 0 Bytes vs main: OK

ydbd size dash	main: d793be5	merge: f9a72df	diff	diff %
ydbd size	4 069 430 064 Bytes	4 069 429 352 Bytes	-712 Bytes	-0.000%
ydbd stripped size	1 510 663 720 Bytes	1 510 663 208 Bytes	-512 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}

[mregrock]

LGTM