feat: update ConvMixer to support reactant #255

Job	Run time
downgrade	1h 8m 46s
test (1, ubuntu-latest, conv, default, true)	30m 56s
test (1, ubuntu-latest, dense, default, true)	18m 32s
test (1, ubuntu-latest, normalization, default, true)	1h 18m 51s
test (1, ubuntu-latest, misc, default, true)	37m 21s
test (1, ubuntu-latest, dense, default, false)	16m 37s
test (1, ubuntu-latest, misc, default, false)	31m 54s
test (1, macos-latest, all, default, true)	1h 59m 5s
test (1, windows-latest, all, default, true)	1h 51m 56s
	8h 33m 58s

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