tests: fix artstation download tests.

Fix ArtStation download tests that were broken when 266e4054 added the
ability to download /4k/ files.

test/unit/downloads/art_station_test.rb

@@ -8,9 +8,9 @@ module Downloads
         @download = Downloads::File.new(@asset)
       end
 
-      should "download the large image instead" do
+      should "download the /4k/ image instead" do
         file, strategy = @download.download!
-        assert_equal(1_550_269, ::File.size(file.path))
+        assert_equal(1_880_910, ::File.size(file.path))
       end
     end
 
@@ -22,7 +22,7 @@ module Downloads
 
       should "not try to download the original" do
         file, strategy = @download.download!
-        assert_equal(382_837, ::File.size(file.path))
+        assert_equal(483_192, ::File.size(file.path))
       end
     end
 
@@ -32,11 +32,11 @@ module Downloads
       end
 
       should "return the original file, not the polished file" do
-        assert_downloaded(1_550_269, @asset)
+        assert_downloaded(1_880_910, @asset)
       end
 
       should "return the original filesize, not the polished filesize" do
-        assert_equal(1_550_269, Downloads::File.new(@asset).size)
+        assert_equal(1_880_910, Downloads::File.new(@asset).size)
       end
     end
 
@@ -49,7 +49,7 @@ module Downloads
       should "download the original image instead" do
         file, strategy = @download.download!
 
-        assert_equal(218_603, ::File.size(file.path))
+        assert_equal(247_350, ::File.size(file.path))
       end
     end
   end