NHentai: fix sorting (fixes #2608)

src/all/nhentai/build.gradle

@@ -5,7 +5,7 @@ ext {
     appName = 'Tachiyomi: NHentai'
     pkgNameSuffix = 'all.nhentai'
     extClass = '.NHFactory'
-    extVersionCode = 18
+    extVersionCode = 19
     libVersion = '1.2'
 }
 

src/all/nhentai/src/eu/kanade/tachiyomi/extension/all/nhentai/NHentai.kt

@@ -140,6 +140,8 @@ open class NHentai(
     }
 
     override fun searchMangaRequest(page: Int, query: String, filters: FilterList): Request {
+        val filters = if (filters.isEmpty()) getFilterList() else filters
+
         val favoriteFilter = filters.findInstance<FavoriteFilter>()
         if (favoriteFilter != null && favoriteFilter.state) {
             val url = HttpUrl.parse("$baseUrl/favorites")!!.newBuilder()