Remove ReferCompleteCallback model, keep only Bxml::Refer verb

The referComplete callback model will land later via a separate
api-specs-driven PR once VAPI-3440 merges. This also removes the
top-level Bandwidth::Refer model (and its ReferCompleteMethodEnum/
ReferCallStatusEnum helpers), which duplicated Bxml::Refer at the
openapi-generator layer and had no equivalent for any other BXML
verb (e.g. Transfer has no top-level Bandwidth::Transfer model).
Adds a spec for Bxml::Refer covering construction with a bare
SipUri and correct BXML rendering.

Author: stampercasey

lib/bandwidth-sdk.rb

@@ -174,10 +174,6 @@
 require 'bandwidth-sdk/models/recording_transcriptions'
 require 'bandwidth-sdk/models/redirect_callback'
 require 'bandwidth-sdk/models/redirect_method_enum'
-require 'bandwidth-sdk/models/refer'
-require 'bandwidth-sdk/models/refer_call_status_enum'
-require 'bandwidth-sdk/models/refer_complete_callback'
-require 'bandwidth-sdk/models/refer_complete_method_enum'
 require 'bandwidth-sdk/models/sip_connection_metadata'
 require 'bandwidth-sdk/models/sip_credentials'
 require 'bandwidth-sdk/models/sip_uri'

lib/bandwidth-sdk/models/bxml/verbs/refer.rb

@@ -1,6 +1,9 @@
 module Bandwidth
   module Bxml
     class Refer < Bandwidth::Bxml::NestableVerb
+      # Initializer
+      # @param sip_uri [SipUri] The SIP URI to REFER the call to. Uses the same SipUri verb shared with Transfer.
+      # @param attributes [Hash] The attributes to add to the element. Defaults to an empty hash.
       def initialize(sip_uri, attributes = {})
         super('Refer', nil, [sip_uri], attributes)
         @attribute_map = {

lib/bandwidth-sdk/models/bxml/verbs/sip_uri.rb

@@ -1,8 +1,10 @@
 module Bandwidth
   module Bxml
     class SipUri < Bandwidth::Bxml::Verb
+      # Shared nested verb used by both Transfer and Refer to specify a SIP URI destination.
+      #
       # Initializer
-      # @param uri [String] A SIP URI to transfer the call to (e.g. sip:user@server.com)
+      # @param uri [String] A SIP URI to transfer or refer the call to (e.g. sip:user@server.com)
       # @param attributes [Hash] The attributes to add to the element. Defaults to an empty hash.
       def initialize(uri, attributes = {})
         super('SipUri', uri, attributes)