staticd: Fix SRv6 SID installation and deletion (backport #18064)

[mergify]

The SRv6 support in staticd (PR #16894) does not set the correct SID parameters (block length, node length, function length).

This PR fixes the issue and computes the correct parameters.

The bug was reported by SONiC testing.

---

This is an automatic backport of pull request #18064 done by Mergify.

[mergify]

Cherry-pick of e1654ba has failed:

On branch mergify/bp/stable/10.2/pr-18064
Your branch is up to date with 'origin/stable/10.2'.

You are currently cherry-picking commit e1654ba55.
  (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)

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

no changes added to commit (use "git add" and/or "git commit -a")

Cherry-pick of a6d02fe has failed:

On branch mergify/bp/stable/10.2/pr-18064
Your branch is ahead of 'origin/stable/10.2' by 2 commits.
  (use "git push" to publish your local commits)

You are currently cherry-picking commit a6d02fe2f.
  (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)

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	deleted by us:   tests/topotests/static_srv6_sids/expected_srv6_sids.json
	deleted by us:   tests/topotests/static_srv6_sids/expected_srv6_sids_sid_delete_1.json
	deleted by us:   tests/topotests/static_srv6_sids/expected_srv6_sids_sid_delete_2.json

no changes added to commit (use "git add" and/or "git commit -a")

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

[cscarpitta]

FRR 10.2 does not have SRv6 support in staticd. This fix is not applicable to 10.2