[ui] make about donation text optional

gui/qml/AboutDialog.qml

@@ -9,15 +9,21 @@ MessageDialog {
     function getText() {
         var _name = ctx ? ctx.appName : "vpn"
         var _provider = ctx ? ctx.provider : "unknown"
-        var _donateURL= ctx ? ctx.donateURL : "..."
+        var _donateURL= ctx ? ctx.donateURL : ""
         var _tosURL = ctx ? ctx.tosURL : "..."
+        var _donateTXT = ""
+        if (_donateURL) {
+            //: donation text of the about dialog
+            //: %1 -> donation URL
+            _donateTXT = qsTr("<p>This service is paid for entirely by donations from users like you. <a href=\"%1\">Please donate</a>.</p>").arg(_donateURL)
+        }
 	//: about dialog
 	//: %1 -> application name
 	//: %2 -> provider name
-	//: %3 -> donation URL
+	//: %3 -> donation text if activated
 	//: %4 -> TOS URL
         var _txt = qsTr(
-            "<p>%1 is an easy, fast, and secure VPN service from %2. %1 does not require a user account, keep logs, or track you in any way.</p> <p>This service is paid for entirely by donations from users like you. <a href=\"%3\">Please donate</a>.</p> <p>By using this application, you agree to the <a href=\"%4\">Terms of Service</a>. This service is provided as-is, without any warranty, and is intended for people who work to make the world a better place.</p>").arg(_name).arg(_provider).arg(_donateURL).arg(_tosURL)
+            "<p>%1 is an easy, fast, and secure VPN service from %2. %1 does not require a user account, keep logs, or track you in any way.</p> %3 <p>By using this application, you agree to the <a href=\"%4\">Terms of Service</a>. This service is provided as-is, without any warranty, and is intended for people who work to make the world a better place.</p>").arg(_name).arg(_provider).arg(_donateTXT).arg(_tosURL)
         return _txt
     }