* refactor(billing): change billing address request type
* feat(billing): add tax id support for international business plans
* feat(billing): add billing address tax id handling
* test: add tests for tax id handling during upgrade
* fix(billing): run dotnet format
* fix(billing): remove extra line
* fix(billing): modify return type of HandleAsync
* test(billing): update tests to reflect updated command signature
* fix(billing): run dotnet format
* tests(billing): fix tests
* test(billing): format
* [PM-29599] create proration preview endpoint
* forgot to inject user and fixing stripe errors
* updated proration preview and upgrade to be consistent
also using the correct proration behavior and making the upgrade flow start a trial
* missed using the billing address
* changes to proration behavior
and returning more properties from the proration endpoint
* missed in refactor
* pr feedback