Fix retrieving incomplete data for SubscriptionEntity

This fixes a visual bug in which the channels reported the the subscriber count was unavailable although stored in the db.

Closes #12953

app/src/main/java/org/schabi/newpipe/database/subscription/SubscriptionEntity.kt

@@ -55,8 +55,8 @@ data class SubscriptionEntity(
     fun toChannelInfoItem(): ChannelInfoItem {
         return ChannelInfoItem(this.serviceId, this.url, this.name).apply {
             thumbnails = ImageStrategy.dbUrlToImageList(this@SubscriptionEntity.avatarUrl)
-            subscriberCount = this.subscriberCount
-            description = this.description
+            subscriberCount = this@SubscriptionEntity.subscriberCount ?: -1
+            description = this@SubscriptionEntity.description
         }
     }