use correct hints when 'All Media' views are empty

deltachat-ios/Controller/DocumentGalleryController.swift

@@ -19,7 +19,7 @@ class DocumentGalleryController: UIViewController {
 
     private lazy var emptyStateView: EmptyStateLabel = {
         let label = EmptyStateLabel()
-        label.text = String.localized("tab_docs_empty_hint")
+        label.text = String.localized(chatId == 0 ? "tab_all_media_empty_hint" : "tab_docs_empty_hint")
         label.isHidden = true
         return label
     }()

deltachat-ios/Controller/GalleryViewController.swift

@@ -43,7 +43,7 @@ class GalleryViewController: UIViewController {
 
     private lazy var emptyStateView: EmptyStateLabel = {
         let label = EmptyStateLabel()
-        label.text = String.localized("tab_gallery_empty_hint")
+        label.text = String.localized(chatId == 0 ? "tab_all_media_empty_hint" : "tab_gallery_empty_hint")
         label.isHidden = true
         return label
     }()