make multi controlnet more robust

[PromeAIpro]

What does this PR do?

Fixes # (issue)

See #9911

when flux multi control is applied and the controlnets not have the same num_layers or num_single_layers, the adding of control_block_samples is not robust (were always cut), causing wrong image result. this PR fix that issue.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline?
• Did you read our philosophy doc (important for complex PRs)?
• Was this discussed/approved via a GitHub issue or the forum? Please add a link to it if that's the case.
• Did you make sure to update the documentation with your changes? Here are the
  documentation guidelines, and
  here are tips on formatting docstrings.
• Did you write any new necessary tests?

Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.

[wuutiing]

is there something blocked? this issue does cause bad result, and not easy to notice @sayakpaul

[sayakpaul]

Please allow a few days to @yiyixuxu or @DN6 to review.