[hotfix] Fix set children rate limit

[camfairchild]

Description

This PR hotfixes the set_children rate limit of 2 tempos for a specific subnet.
Includes a test for the hotfix.

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Other (please describe):

Breaking Change

If this PR introduces a breaking change, please provide a detailed description of the impact and the migration path for existing applications.

Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have run cargo fmt and cargo clippy to ensure my code is formatted and linted correctly
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[github-actions]

🚨🚨🚨 HOTFIX DETECTED 🚨🚨🚨

It looks like you are trying to merge a hotfix PR into . If this isn't what you wanted to do, and you just wanted to make a regular PR, please close this PR, base your changes off the branch and open a new PR into .

If you are trying to merge a hotfix PR, please complete the following essential steps:

1. go ahead and get this PR into main merged, so we can get the change in as quickly as possible!
2. merge main into testnet, bumping spec_version
3. deploy testnet
4. merge testnet into devnet, bumping spec_version
5. deploy devnet
6. merge devnet into devnet-ready

If you do not complete these steps, your hotfix may be inadvertently removed in the future when branches are promoted to main, so it is essential that you do so.

[distributedstatemachine]

this change breaks alot of the existing tests .

failures:
    test_do_revoke_child_singular_success
    test_do_revoke_children_multiple_complex_scenario
    test_do_revoke_children_multiple_non_existent_children
    test_do_revoke_children_multiple_partial_revocation
    test_do_revoke_children_multiple_success
    test_do_set_child_singular_multiple_children
    test_do_set_child_singular_old_children_cleanup
    test_do_set_child_singular_proportion_edge_cases
    test_do_set_children_multiple_old_children_cleanup
    test_do_set_children_multiple_overwrite_existing

can you please patch these ?

[camfairchild]

this change breaks alot of the existing tests .

failures:
    test_do_revoke_child_singular_success
    test_do_revoke_children_multiple_complex_scenario
    test_do_revoke_children_multiple_non_existent_children
    test_do_revoke_children_multiple_partial_revocation
    test_do_revoke_children_multiple_success
    test_do_set_child_singular_multiple_children
    test_do_set_child_singular_old_children_cleanup
    test_do_set_child_singular_proportion_edge_cases
    test_do_set_children_multiple_old_children_cleanup
    test_do_set_children_multiple_overwrite_existing

can you please patch these ?

Should be fixed with new step_rate_limit helper