refactor(identify): use function call to validate Multiaddr

[LVivona]

Description

Going through the protocols within libp2p to understand the repo. I found that incorporating a function call in this instance enhanced the readability and flow of the code.

Notes & open questions

• This commit is a subjective opinion.
• If this is something to check if it's a valid tcp, udp/quic or other, then I would be happy to apply it within libp2p-core as some sort of utility function.

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

[elenaf9]

Thank you for the PR @LVivona, but I am not sure if extracting that logic into a separate function is really an improvement here. Especially when it's only used in a single place.

[LVivona]

Thank you for the reply @elenaf9, I do agree there is little to no logical benefit especially since it's used once as you mentioned, it is mainly a more subjective one when I was going though the protocol code, it just simplified the contract of the if statement, though I may be alone in thinking that way. :)

feel free to close the pull request if you feel like my reason is in-sufficient.