fix simple reader destruction

[swalrus1]

Changelog entry

Fix crashing on CS reader destruction when actor system is stopped

Changelog category

• Bugfix

Description for reviewers

#22653

[github-actions]

🟢 2025-08-14 14:52:18 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-08-14 14:54:13 UTC Pre-commit check linux-x86_64-release-asan for 3ff8fd9 has started.
⚪ 2025-08-14 14:54:28 UTC Artifacts will be uploaded here
⚪ 2025-08-14 14:57:40 UTC ya make is running...
🟡 2025-08-14 16:44:29 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Test history | Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
14528	14136	0	113	258	21

🟢 2025-08-14 16:45:43 UTC Build successful.
🟢 2025-08-14 16:46:11 UTC ydbd size 4.0 GiB changed* by -48 Bytes, which is <= 0 Bytes vs main: OK

ydbd size dash	main: 37d2fe9	merge: 3ff8fd9	diff	diff %
ydbd size	4 272 762 240 Bytes	4 272 762 192 Bytes	-48 Bytes	-0.000%
ydbd stripped size	1 480 994 136 Bytes	1 480 994 136 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]

⚪ 2025-08-14 14:55:28 UTC Pre-commit check linux-x86_64-relwithdebinfo for 3ff8fd9 has started.
⚪ 2025-08-14 14:55:43 UTC Artifacts will be uploaded here
⚪ 2025-08-14 14:59:04 UTC ya make is running...
🟡 2025-08-14 16:10:56 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?
29808	28414	0	1	1364	29

⚪ 2025-08-14 16:13:43 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-08-14 16:28:42 UTC Tests successful.

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

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
207 (only retried tests)	183	0	0	0	24

🟢 2025-08-14 16:28:49 UTC Build successful.
🟢 2025-08-14 16:29:08 UTC ydbd size 2.3 GiB changed* by +144 Bytes, which is < 100.0 KiB vs main: OK

ydbd size dash	main: b14da24	merge: 3ff8fd9	diff	diff %
ydbd size	2 428 296 232 Bytes	2 428 296 376 Bytes	+144 Bytes	+0.000%
ydbd stripped size	508 675 304 Bytes	508 675 304 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}