MangaPresenter: Always fetch chapter from source if current chapter is empty (#7507)

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaPresenter.kt

@@ -189,6 +189,8 @@ class MangaPresenter(
 
                     if (!manga.initialized) {
                         fetchAllFromSource(manualFetch = false)
+                    } else if (chapterItems.isEmpty()) {
+                        fetchChaptersFromSource()
                     }
                 }
         }