pim: Fix vrf binding of autorp and mroute socket (backport #18226)

[mergify]

Bind the autorp socket to the vrf device.
Also fixed mroute socket to use vrf_bind instead of directly setting the socket option.

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This is an automatic backport of pull request #18226 done by Mergify.

[mergify]

Cherry-pick of 7e181a7 has failed:

On branch mergify/bp/stable/10.2/pr-18226
Your branch is up to date with 'origin/stable/10.2'.

You are currently cherry-picking commit 7e181a771.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   pimd/pim_autorp.h
	modified:   pimd/pim_instance.c
	modified:   pimd/pim_mroute.c

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   pimd/pim_autorp.c

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally