enable "ALL" in Browse by default (#6023)

some extensions, including self-hosted ones, have the "ALL" label and
sometimes users get confused with not having enabled "ALL" after
installing new extensions

app/src/main/java/eu/kanade/tachiyomi/data/preference/PreferencesHelper.kt

@@ -190,7 +190,7 @@ class PreferencesHelper(val context: Context) {
 
     fun sourceDisplayMode() = flowPrefs.getEnum(Keys.sourceDisplayMode, DisplayModeSetting.COMPACT_GRID)
 
-    fun enabledLanguages() = flowPrefs.getStringSet(Keys.enabledLanguages, setOf("en", Locale.getDefault().language))
+    fun enabledLanguages() = flowPrefs.getStringSet(Keys.enabledLanguages, setOf("all", "en", Locale.getDefault().language))
 
     fun trackUsername(sync: TrackService) = prefs.getString(Keys.trackUsername(sync.id), "")