Rename Project#create_or_update_import_data to Project#build_or_assign_import_data

Summary

Rename Project#create_or_update_import_data to Project#build_or_assign_import_data as it doesn't save record.

Improvements

To avoid confusion "Why doesn't it save the ProjectImportData record?"

Risks

Method is used in multiple places. In few of them changes could trigger rubocop's check fails. What will lead us to refactor code a little that could potentially broke something.