♻️ Refactor territory-bro.gis-sync/refresh!
♻️ Refactor territory-bro.gis-sync/refresh!

Why:
- Using a private function instead of overloaded arguments makes it
  more explicit that the private function is not meant to be called
  directly
- Also combining a nested `let` and `if` into an `if-some`
- Not extracting composed functions from the two if cases, because the
  "conflict branch" would require many function arguments, and the
  "no conflict branch" passes on many return values, so it would be hard
  to extract a cohesive function out of it

orfjackal/territory-bro,orfjackal/territory-bro,orfjackal/territory-bro