Stub generation omits original_name for getReportDownloadURL

As reported in PR https://github.com/googleads/google-api-ads-ruby/pull/202/ the latest stub generation doesn't include the original name mapping. Savon defaults to converting from snake_case to camelCase and calls the non-existent getReportDownloadUrl instead of getReportDownloadURL

Example stack trace:

versions/3.4.1/lib/ruby/gems/3.4.0/gems/google-ads-common-3.0.0/lib/ads_common/savon_service.rb:121:in 'AdsCommon::SavonService#handle_errors': Unknown exception with error: Message part {https://www.google.com/apis/ads/publisher/v202505}getReportDownloadUrl was not recognized.  (Does it exist in service WSDL?) (AdsCommon::Errors::ApiException)
        from /usr/local/google/home/cseeley/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/google-ads-common-3.0.0/lib/ads_common/savon_service.rb:94:in 'AdsCommon::SavonService#execute_action'
        from /usr/local/google/home/cseeley/.rbenv/versions/3.4.1/lib/ruby/gems/3.4.0/gems/google-dfp-api-4.1.0/lib/ad_manager_api/v202505/report_service.rb:21:in 'AdManagerApi::V202505::ReportService::ReportService#get_report_download_url'

Start by reviewing PR #202 and the generated versions/3.4.1/lib/ruby/gems/3.4.0/gems/google-dfp-api-4.1.0/lib/ad_manager_api/v202505/report_service.rb referenced in the stack trace. Reproduce the get_report_download_url failure and trace how stub generation handles original_name; done means the generated call uses the WSDL operation getReportDownloadURL rather than getReportDownloadUrl.