JSON encode'ing `IncomingPhoneNumber` loses `capabilities`

[stevebauman]

The IncomingPhoneNumberInstance class extends the InstanceResource which has the toArray() method defined:

twilio-php/src/Twilio/InstanceResource.php

Lines 17 to 19 in 248dce8

	public function toArray(): array {
	return $this->properties;
	}

But the PhoneNumberCapabilities does not include a toArray() method:

https://github.com/twilio/twilio-php/blob/main/src/Twilio/Base/PhoneNumberCapabilities.php

This results in the JSON encoded instance missing capabilities:

Notice how "capabilities" are empty:

{
   "accountSid":"...",
   "addressSid":null,
   "addressRequirements":"none",
   "apiVersion":"2010-04-01",
   "beta":false,
   "capabilities":{
      
   },
   "dateCreated":{
      "date":"2021-10-22 08:17:04.000000",
      "timezone_type":1,
      "timezone":"+00:00"
   },
   "dateUpdated":{
      "date":"2025-07-11 00:27:35.000000",
      "timezone_type":1,
      "timezone":"+00:00"
   },
   "friendlyName":"...",
   "identitySid":null,
   "phoneNumber":"...",
   "origin":"twilio",
   "sid":"...",
   "smsApplicationSid":"",
   "smsFallbackMethod":"POST",
   "smsFallbackUrl":"",
   "smsMethod":"POST",
   "smsUrl":"https:\/\/....com\/telephony\/messages\/twilio",
   "statusCallback":"",
   "statusCallbackMethod":"POST",
   "trunkSid":null,
   "uri":"\/2010-04-01\/Accounts\/...\/IncomingPhoneNumbers\/....json",
   "voiceReceiveMode":"voice",
   "voiceApplicationSid":"",
   "voiceCallerIdLookup":false,
   "voiceFallbackMethod":"POST",
   "voiceFallbackUrl":"",
   "voiceMethod":"POST",
   "voiceUrl":"http:\/\/realtime-websocket-dev.us-east-1.elasticbeanstalk.com:8081\/twiml",
   "emergencyStatus":"Active",
   "emergencyAddressSid":null,
   "emergencyAddressStatus":"unregistered",
   "bundleSid":null,
   "status":"in-use"
}