[ios] fix terms dialog on first launch

iphone/Maps/Classes/MapViewController.mm

@@ -243,7 +243,7 @@ BOOL gIsFirstMyPositionMode = YES;
 
   [self updateStatusBarStyle];
   GetFramework().InvalidateRendering();
-  [self showWelcomeScreenIfNeeded];
+  [self.welcomePageController show];
   [self showViralAlertIfNeeded];
   [self checkAuthorization];
 }
@@ -254,6 +254,7 @@ BOOL gIsFirstMyPositionMode = YES;
   self.view.clipsToBounds = YES;
   [self processMyPositionStateModeEvent:MWMMyPositionModePendingPosition];
   [MWMKeyboard addObserver:self];
+  self.welcomePageController = [MWMWelcomePageController controllerWithParent:self];
 }
 
 - (void)mwm_refreshUI
@@ -264,11 +265,6 @@ BOOL gIsFirstMyPositionMode = YES;
   [self.downloadDialog mwm_refreshUI];
 }
 
-- (void)showWelcomeScreenIfNeeded
-{
-  self.welcomePageController = [MWMWelcomePageController controllerWithParent:self];
-}
-
 - (void)closePageController:(MWMWelcomePageController *)pageController
 {
   if ([pageController isEqual:self.welcomePageController])

iphone/Maps/UI/Welcome/WelcomePageController.swift

@@ -61,7 +61,6 @@ final class WelcomePageController: UIPageViewController {
       controller.delegate = vc
     }
     vc.controllers = controllersToShow
-    vc.show()
     return vc
   }
 
@@ -101,7 +100,7 @@ final class WelcomePageController: UIPageViewController {
     MWMFrameworkHelper.processFirstLaunch()
   }
 
-  func show() {
+  @objc func show() {
     if let controller = currentController as? WelcomeViewController {
       Statistics.logEvent(kStatEventName(kStatWhatsNew, type(of: controller).key),
                           withParameters: [kStatAction: kStatOpen])