[dart-dio] Fix webhook imports generating Map-style strings#22611

Lutra-Fs wants to merge 3 commits intoOpenAPITools:masterOpenAPITools/openapi-generator:masterfrom

Lutra-Fs:fix/issue-22586-dart-dio-webhook-importsLutra-Fs/openapi-generator:fix/issue-22586-dart-dio-webhook-importsCopy head branch name to clipboard