fix: remove duplicate field entries

[software-dov]

Fix for #778

[codecov]

Codecov Report

Merging #786 (5ff544a) into master (7c185e8) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #786   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           26        27    +1     
  Lines         1608      1623   +15     
  Branches       328       330    +2     
=========================================
+ Hits          1608      1623   +15     

Impacted Files	Coverage Δ
gapic/utils/case.py	100.00% <ø> (ø)
gapic/generator/generator.py	100.00% <100.00%> (ø)
gapic/schema/wrappers.py	100.00% <100.00%> (ø)
gapic/utils/__init__.py	100.00% <100.00%> (ø)
gapic/utils/checks.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 35338fc...5ff544a. Read the comment docs.