Fix: Fix size matcher for `has_many_attached` attachments #205

Job	Run time
minitest (2.6, rails_6_0, vips)	54s
minitest (2.6, rails_6_0, mini_magick)	38s
minitest (2.6, rails_6_1, vips)	45s
minitest (2.6, rails_6_1, mini_magick)	1m 7s
minitest (2.7, rails_6_0, vips)	1m 3s
minitest (2.7, rails_6_0, mini_magick)	1m 11s
minitest (2.7, rails_6_1, vips)	50s
minitest (2.7, rails_6_1, mini_magick)	1m 1s
minitest (2.7, rails_7_0, vips)	59s
minitest (2.7, rails_7_0, mini_magick)	1m 5s
minitest (2.7, rails_next, vips)	1m 0s
minitest (2.7, rails_next, mini_magick)	48s
minitest (3.0, rails_6_1, vips)	28s
minitest (3.0, rails_6_1, mini_magick)	45s
minitest (3.0, rails_7_0, vips)	29s
minitest (3.0, rails_7_0, mini_magick)	38s
minitest (3.0, rails_next, vips)	40s
minitest (3.0, rails_next, mini_magick)	41s
minitest (3.1, rails_7_0, vips)	29s
minitest (3.1, rails_7_0, mini_magick)	40s
minitest (3.1, rails_next, vips)	47s
minitest (3.1, rails_next, mini_magick)	37s
minitest (3.2, rails_7_0, vips)	30s
minitest (3.2, rails_7_0, mini_magick)	32s
minitest (3.2, rails_next, vips)	41s
minitest (3.2, rails_next, mini_magick)	1m 0s
	20m 18s

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