Fix for "java.lang.IllegalArgumentException: unexpected url" (#313)

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@RocketChat/ReactNative

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User was able to add an invalid instance of Rocket.Chat by pressing submit button instead of "Connect" button.

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app/views/NewServerView.js

@@ -48,8 +48,10 @@ export default class NewServerView extends LoggedView {
 	}
 
 	submit = () => {
-		Keyboard.dismiss();
-		this.props.addServer(this.completeUrl(this.state.text));
+		if (this.props.validInstance) {
+			Keyboard.dismiss();
+			this.props.addServer(this.completeUrl(this.state.text));
+		}
 	}
 
 	completeUrl = (url) => {