fix mangadex titles having "" (#8037)

src/all/mangadex/build.gradle

@@ -6,7 +6,7 @@ ext {
     extName = 'MangaDex'
     pkgNameSuffix = 'all.mangadex'
     extClass = '.MangaDexFactory'
-    extVersionCode = 122
+    extVersionCode = 123
     libVersion = '1.2'
     containsNsfw = true
 }

src/all/mangadex/src/eu/kanade/tachiyomi/extension/all/mangadex/dto/MangaDto.kt

@@ -3,6 +3,8 @@ package eu.kanade.tachiyomi.extension.all.mangadex.dto
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.JsonObject
+import kotlinx.serialization.json.contentOrNull
+import kotlinx.serialization.json.jsonPrimitive
 
 @Serializable
 data class MangaListDto(
@@ -59,6 +61,6 @@ data class TagDto(
 
 fun JsonElement.asMdMap(): Map<String, String> {
     return runCatching {
-        (this as JsonObject).map { it.key to it.value.toString() }.toMap()
+        (this as JsonObject).map { it.key to (it.value.jsonPrimitive.contentOrNull ?: "") }.toMap()
     }.getOrElse { emptyMap() }
 }