fix(ping): honor ping interval in case of errors

[dariusc93]

Description

This PR adds a delay to ping connection handler after exceeding the failure rate to prevent opening a outbound stream right after an error.

Resolves #4410.

Notes & open questions

1. Would it be better to switch failures to a boolean instead?

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• A changelog entry has been made in the appropriate crates

[thomaseizinger]

1. Would it be better to switch failures to a boolean instead?

I don't think we can make it a boolean. The behaviour we need to retain is that the first error is "free", i.e. doesn't cause any problems. We want to be compatible with an implementation that uses one stream per ping. (Do we actually have a test for that?)

I am open to changing the impl here but I'd prefer if that happens in a different PR and we focus this one on the fix for the stream spam.

Made them myself.

[mxinden]

Looks good to me, but deferring to @thomaseizinger. Thank you for the work here.