feature: added subscription expiration date for premium v2 (#1261)

* feature: added subscription expiration date for premium v2

* feature: added a check for the presence of the “services” field in the response body of the getServicesList() function

* feature: added prohibition to change location when connection is active

* bugfix: renamed public_key->end_date to public_key->expires_at according to the changes on the backend

client/ui/qml/Pages2/PageSettingsApiLanguageList.qml

@@ -54,8 +54,14 @@ PageType {
                         imageSource: "qrc:/images/controls/download.svg"
 
                         checked: index === ApiCountryModel.currentIndex
+                        checkable: !ConnectionController.isConnected
 
                         onClicked: {
+                            if (ConnectionController.isConnected) {
+                                PageController.showNotificationMessage(qsTr("Unable change server location while there is an active connection"))
+                                return
+                            }
+
                             if (index !== ApiCountryModel.currentIndex) {
                                 PageController.showBusyIndicator(true)
                                 var prevIndex = ApiCountryModel.currentIndex