CB-11815: (iOS) Fix hard-coded bridge name "cordova"

 This closes #18
diff --git a/src/ios/CDVWKWebViewEngine.m b/src/ios/CDVWKWebViewEngine.m
index 8039dcc..f60eace 100644
--- a/src/ios/CDVWKWebViewEngine.m
+++ b/src/ios/CDVWKWebViewEngine.m
@@ -98,7 +98,7 @@
     }
 
     if ([self.viewController conformsToProtocol:@protocol(WKScriptMessageHandler)]) {
-        [wkWebView.configuration.userContentController addScriptMessageHandler:(id < WKScriptMessageHandler >)self.viewController name:@"cordova"];
+        [wkWebView.configuration.userContentController addScriptMessageHandler:(id < WKScriptMessageHandler >)self.viewController name:CDV_BRIDGE_NAME];
     }
 
     [self updateSettings:settings];