fix(ios): return the string of the URL in classification success

Author: timmywil

example/ios/Podfile.lock

@@ -186,7 +186,7 @@ PODS:
     - React-cxxreact (= 0.63.4)
     - React-jsi (= 0.63.4)
   - React-jsinspector (0.63.4)
-  - react-native-spokestack (5.0.0-beta.0):
+  - react-native-spokestack (5.0.0-beta.4):
     - React
     - Spokestack-iOS (= 14.0.1)
   - React-RCTActionSheet (0.63.4):
@@ -374,7 +374,7 @@ SPEC CHECKSUMS:
   React-jsi: a0418934cf48f25b485631deb27c64dc40fb4c31
   React-jsiexecutor: 93bd528844ad21dc07aab1c67cb10abae6df6949
   React-jsinspector: 58aef7155bc9a9683f5b60b35eccea8722a4f53a
-  react-native-spokestack: 28af19051ba6ad0c30b7d87193845dd517d20ff2
+  react-native-spokestack: f4210156eb4087f951ffc45f04070afdf11449e7
   React-RCTActionSheet: 89a0ca9f4a06c1f93c26067af074ccdce0f40336
   React-RCTAnimation: 1bde3ecc0c104c55df246eda516e0deb03c4e49b
   React-RCTBlob: a97d378b527740cc667e03ebfa183a75231ab0f0

ios/RNSpokestack.swift

@@ -154,7 +154,7 @@ class RNSpokestack: RCTEventEmitter, SpokestackDelegate {
 
     func success(result: TextToSpeechResult) {
         if let resolve = resolvers.removeValue(forKey: RNSpokestackPromise.synthesize) {
-            resolve(result.url)
+            resolve(result.url?.absoluteString)
             rejecters.removeValue(forKey: RNSpokestackPromise.synthesize)
         } else if let resolve = resolvers.removeValue(forKey: RNSpokestackPromise.speak) {
             resolve(nil)