auto-subscribe fails when issue body is large

[danilaml]

See https://github.com/llvm/llvm-project/actions/runs/18784813915/job/53600195802 that failed for #165004

[llvmbot]

@llvm/issue-subscribers-infrastructure

Author: Danila Malyutin (danilaml)

See https://github.com/llvm/llvm-project/actions/runs/18784813915/job/53600195802 that failed for https://github.com//issues/165004