Golang net: WriteMsgUDPAddrPort should accept IPv4-mapped IPv6 destination addresses on IPv4 UDP sockets [1.25 backport]

@dr2chase requested issue #74737 to be considered for backport to the next 1.25 minor release.

@gopherbot, please backport to 1.25

Comment From: gopherbot

Change https://go.dev/cl/695875 mentions this issue: [release-branch.go1.25] net: fix WriteMsgUDPAddrPort addr handling on IPv4 sockets