Please fix WKWebView for embedded iframe

[Yambr]

Hi!)
I found some problem and fixed it look at url below:
https://github.com/Yambr/nativescript-webview-utils/pull/1/files

Problem:
If you are adding some headers to WKWebView (or WebView on iOS) for url with embedded iframe - WebView redirecting to iframe url

How i fixed:
if target frame is main = false - ignore them

steps to reproduce and screenshots here Yambr#1

Thanks!)