chore: remove UIWebView comment and variable (#538)

Author: jcesarmobile

src/ios/CDVWKWebViewEngine.m

@@ -526,7 +526,6 @@ - (void)updateWithInfo:(NSDictionary *)info
 }
 
 // This forwards the methods that are in the header that are not implemented here.
-// Both WKWebView and UIWebView implement the below:
 //     loadHTMLString:baseURL:
 //     loadRequest:
 - (id)forwardingTargetForSelector:(SEL)aSelector
@@ -740,7 +739,11 @@ - (void) webView:(WKWebView *)webView decidePolicyForNavigationAction:(WKNavigat
             // https://issues.apache.org/jira/browse/CB-12497
             int navType = (int)navigationAction.navigationType;
             if (WKNavigationTypeOther == navigationAction.navigationType) {
-                navType = (int)UIWebViewNavigationTypeOther;
+                #ifdef __CORDOVA_6_0_0
+                    navType = -1;
+                #else
+                    navType = 5;
+                #endif
             }
             shouldAllowRequest = (((BOOL (*)(id, SEL, id, int))objc_msgSend)(plugin, selector, navigationAction.request, navType));
             if (!shouldAllowRequest) {