Make sanitizers CI gate blocking: fix all findings

[lavrovvalera]

Important

Link the implementing PR to this issue by including Closes #<issue_number>
in the PR description or commit message.

What

Remove continue-on-error: true from the QA / Sanitizers CI job so that
unresolved sanitizer findings block PR merges.

The flag was added intentionally when the job was introduced because the codebase
had pre-existing sanitizer findings. Once all findings tracked in #76, #77, #78, #79
are fixed, this gate can be made blocking.

Acceptance Criteria

• All ASan/UBSan/LSan findings resolved across all components (see Fix SCA and sanitizer findings: score/time #76, Fix SCA and sanitizer findings: score/time_daemon #77, Fix SCA and sanitizer findings: score/time_slave #78, Fix SCA and sanitizer findings: score/ts_client #79)
• continue-on-error: true removed from the sanitizers job in .github/workflows/sanitizers.yml
• QA / Sanitizers CI job passes without findings on a clean branch

References

• Sanitizers CI job introduced in: Add sanitizer CI (ASAN/TSAN/UBSAN) #43
• SCA fix tasks (blockers): Fix SCA and sanitizer findings: score/time #76, Fix SCA and sanitizer findings: score/time_daemon #77, Fix SCA and sanitizer findings: score/time_slave #78, Fix SCA and sanitizer findings: score/ts_client #79