MangaGeko: Fix missing images in getPages (#2267)

src/main/kotlin/org/koitharu/kotatsu/parsers/site/en/MangaGeko.kt

@@ -159,12 +159,15 @@ internal class MangaGeko(context: MangaLoaderContext) :
     override suspend fun getPages(chapter: MangaChapter): List<MangaPage> {
         val fullUrl = chapter.url.toAbsoluteUrl(domain)
         val doc = webClient.httpGet(fullUrl).parseHtml()
-
-		return doc.requireElementById("chapter-reader").select("img").map { img ->
-			val url = img.requireSrc().toRelativeUrl(domain)
+        return doc.select("center img")
+            .mapNotNull { it.attr("src").takeIf { src -> src.isNotBlank() } }
+            // remove all invaild images + credits
+            .filterNot { it.startsWith("data:image") || it.contains("credits-mgeko.png") }
+            .distinct().map { url ->
+                val finalUrl = url.toRelativeUrl(domain)
                 MangaPage(
-				id = generateUid(url),
-				url = url,
+                    id = generateUid(finalUrl),
+                    url = finalUrl,
                     preview = null,
                     source = source,
                 )