fix: south africa vat patch failure (backport #27323)

[mergify]

reload doc is necessary on new doctypes

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This is an automatic backport of pull request #27323 done by Mergify.

[mergify]

Cherry-pick of d1fe060 has failed:

On branch mergify/bp/version-13-hotfix/pr-27323
Your branch is up to date with 'origin/version-13-hotfix'.

You are currently cherry-picking commit d1fe060e4a.
  (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:   erpnext/patches/v13_0/add_custom_field_for_south_africa.py

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