Fix "method_complexity" issue in lib/open_api_annotator/components_builder.rb

[ngtk]

Method build_has_many_association_properties has a Cognitive Complexity of 8 (exceeds 5 allowed). Consider refactoring.

https://codeclimate.com/github/ngtk/open_api_annotator/lib/open_api_annotator/components_builder.rb#issue_5b134a623878fa0001000027