lib, test: fix display ipv4 mapped ipv6 addresses

[louis-6wind]

Display ipv4 mapped ipv6 addresses in the format ::ffff:A.B.C.D.

[riw777]

should this be put in together with https://github.com/FRRouting/frr/pull/16439 ?? would it pass ci if these were one commit?

[mwinter-osr]

CI:rerun

[github-actions[bot]]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[riw777]

@Mergifyio rebase

[mergify[bot]]

rebase

☑️ Nothing to do

• [ ] -conflict [📌 rebase requirement]
• [X] -closed [📌 rebase requirement]
• [X] queue-position = -1 [📌 rebase requirement]
• [X] any of:
  • [X] #commits > 1 [📌 rebase requirement]
  • [X] #commits-behind > 0 [📌 rebase requirement]
  • [ ] -linear-history [📌 rebase requirement]

[riw777]

the conflicts need to be fixed on this and it needs to be rebased so we can try to get it through ci ...