Changes to Get user account

the account_type response's property type changed from string to no type for status 200

added the non-success response with the status 400

added the non-success response with the status 401

added the non-success response with the status 404

added the non-success response with the status 429

added UserAccountType to the account_type response property allOf list for the response status 200

removed the BUSINESS enum value from the account_type response property for the response status 200

removed the PINNER enum value from the account_type response property for the response status 200

the endpoint scheme security client_credentials was added to the API

added the optional property about to the response with the 200 status

added the optional property id to the response with the 200 status

added the optional property board_count to the response with the 200 status

added the optional property business_name to the response with the 200 status

added the optional property follower_count to the response with the 200 status

added the optional property following_count to the response with the 200 status

added the optional property monthly_views to the response with the 200 status

added the optional property pin_count to the response with the 200 status

for the query request parameter ad_account_id, the maxLength was set to 18

changed the pattern of the query request parameter ad_account_id from \d+ to ^\d+$

added the non-success response with the status 403