fix: set appropriate error message for decimal types in arrow

[agoose77]

Fixes #1870

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📚 The documentation for this PR will be available at https://awkward-array.readthedocs.io/en/agoose77-fix-from-arrow-error/ once Read the Docs has finished building 🔨

[codecov]

Codecov Report

Merging #1871 (7801f58) into main (21c81e1) will decrease coverage by 0.01%.
The diff coverage is n/a.

Additional details and impacted files

Impacted Files	Coverage Δ
src/awkward/_connect/pyarrow.py	88.46% <ø> (ø)
src/awkward/contents/indexedarray.py	76.60% <0.00%> (-0.19%)	⬇️
src/awkward/contents/recordarray.py	83.87% <0.00%> (-0.19%)	⬇️
src/awkward/_util.py	82.42% <0.00%> (-0.18%)	⬇️
src/awkward/contents/indexedoptionarray.py	88.90% <0.00%> (-0.16%)	⬇️
src/awkward/_connect/avro.py	87.17% <0.00%> (-0.14%)	⬇️
src/awkward/types/_awkward_datashape_parser.py	47.72% <0.00%> (-0.01%)	⬇️

[jpivarski]

Just making it a little more specific, so users know what to look for.