remove placeholder for loadAvatarInternal

this looks smoother when loading the avatars (less flickering)
"error" and "fallback" take over if something goes wrong.

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

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

@@ -134,7 +134,6 @@ private fun ImageView.loadAvatarInternal(
                 )
             }
             transformations(CircleCropTransformation())
-            placeholder(placeholder ?: ContextCompat.getDrawable(context, R.drawable.account_circle_96dp))
             error(placeholder ?: ContextCompat.getDrawable(context, R.drawable.account_circle_96dp))
             fallback(placeholder ?: ContextCompat.getDrawable(context, R.drawable.account_circle_96dp))
             listener(onError = { _, result ->