Apply documented defaults to format options

[JordanNoone]

Summary

• apply existing defaults when OBJ, PLY, STL, and glTF option fields are omitted
• add a regression test for minimal import and export payloads
• regenerate OpenAPI so defaulted fields are no longer marked required

Tests

• cargo +1.96.0 test -p kittycad-modeling-cmds documented_format_defaults_are_applied_when_omitted
• EXPECTORATE=overwrite cargo +1.96.0 test -p kittycad-modeling-cmds --all-features test_openapi -- --nocapture
• cargo +1.96.0 clippy -p kittycad-modeling-cmds --tests -- -D warnings

Closes #1300

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
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Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1353   +/-   ##
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  Coverage        ?   36.12%           
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  Files           ?       36           
  Lines           ?     1813           
  Branches        ?        0           
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  Hits            ?      655           
  Misses          ?     1158           
  Partials        ?        0           

Flag	Coverage Δ
unittests	36.12% <100.00%> (?)

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