fix to show placeholder avatar when none is set by user

Signed-off-by: Marcel Hibbe <dev@mhibbe.de>

app/src/main/java/com/nextcloud/talk/adapters/items/ConversationItem.kt

@@ -184,7 +184,7 @@ class ConversationItem(
                 ConversationType.ROOM_GROUP_CALL,
                 ConversationType.FORMER_ONE_TO_ONE,
                 ConversationType.ROOM_PUBLIC_CALL ->
-                    holder.binding.dialogAvatar.loadConversationAvatar(user, model)
+                    holder.binding.dialogAvatar.loadConversationAvatar(user, model, false)
 
                 else -> holder.binding.dialogAvatar.visibility = View.GONE
             }

app/src/main/java/com/nextcloud/talk/conversationinfo/ConversationInfoActivity.kt

@@ -807,7 +807,7 @@ class ConversationInfoActivity :
             }
 
             Conversation.ConversationType.ROOM_GROUP_CALL, Conversation.ConversationType.ROOM_PUBLIC_CALL -> {
-                binding.avatarImage.loadConversationAvatar(conversationUser, conversation!!)
+                binding.avatarImage.loadConversationAvatar(conversationUser, conversation!!, true)
             }
 
             Conversation.ConversationType.ROOM_SYSTEM -> {

app/src/main/java/com/nextcloud/talk/conversationinfoedit/ConversationInfoEditActivity.kt

@@ -359,7 +359,7 @@ class ConversationInfoEditActivity :
             }
 
             Conversation.ConversationType.ROOM_GROUP_CALL, Conversation.ConversationType.ROOM_PUBLIC_CALL -> {
-                binding.avatarImage.loadConversationAvatar(conversationUser, conversation!!)
+                binding.avatarImage.loadConversationAvatar(conversationUser, conversation!!, true)
             }
 
             Conversation.ConversationType.ROOM_SYSTEM -> {

app/src/main/java/com/nextcloud/talk/extensions/ImageViewExtensions.kt

@@ -54,9 +54,12 @@ private const val TAG = "ImageViewExtensions"
 
 fun ImageView.loadConversationAvatar(
     user: User,
-    conversation: Conversation
+    conversation: Conversation,
+    ignoreCache: Boolean
 ): io.reactivex.disposables
 .Disposable {
+    var finalIgnoreCache = ignoreCache
+
     val imageRequestUri = ApiUtils.getUrlForConversationAvatarWithVersion(
         1,
         user.baseUrl,
@@ -64,6 +67,10 @@ fun ImageView.loadConversationAvatar(
         conversation.avatarVersion
     )
 
+    if (conversation.avatarVersion.isNullOrEmpty()) {
+        finalIgnoreCache = true
+    }
+
     // these placeholders are only used when the request fails completely. The server also return default avatars
     // when no own images are set. (although these default avatars can not be themed for the android app..)
     val placeholder =
@@ -77,7 +84,7 @@ fun ImageView.loadConversationAvatar(
             else -> ContextCompat.getDrawable(context, R.drawable.account_circle_96dp)
         }
 
-    return loadAvatarInternal(user, imageRequestUri, false, placeholder)
+    return loadAvatarInternal(user, imageRequestUri, finalIgnoreCache, placeholder)
 }
 
 fun ImageView.loadUserAvatar(