Merge branch 'dm-empty-blob-viewer-binary' into 'master'

Empty blob viewer isn’t binary-only

See merge request !11979

app/models/blob.rb

@@ -180,7 +180,7 @@ class Blob < SimpleDelegator
   end
 
   def rendered_as_text?(ignore_errors: true)
-    simple_viewer.text? && (ignore_errors || simple_viewer.render_error.nil?)
+    simple_viewer.is_a?(BlobViewer::Text) && (ignore_errors || simple_viewer.render_error.nil?)
   end
 
   def show_viewer_switcher?

app/models/blob_viewer/empty.rb

@@ -4,6 +4,5 @@ module BlobViewer
     include ServerSide
 
     self.partial_name = 'empty'
-    self.binary = true
   end
 end