BUG: fix reading coordinates in `Fargo3DReader.read` #1803

Job	Run time
Image tests	17s
type-checking (3.9)	29s
tests (ubuntu-latest, 3.9, bin)	55s
type-checking (3.10)	29s
tests (ubuntu-latest, 3.10, bin)	58s
type-checking (3.11)	41s
tests (ubuntu-latest, 3.11, bin)	58s
type-checking (3.12)	37s
tests (ubuntu-latest, 3.12, bin)	1m 14s
type-checking (3.13)	43s
tests (ubuntu-latest, 3.13, bin)	1m 22s
tests (ubuntu-20.04, 3.9, bin, minimal, --resolution=lowest-direct)	1m 9s
tests (macos-latest, 3.13, bin)	1m 5s
tests (windows-latest, 3.13, Scripts)	2m 38s
docs	9s
Combine coverage reports	14s
	13m 58s

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