Add basic axe core testing for blocks #2672

Job	Run time
build	4m 8s
test (ruby 3.3 / rails ~> 7.2 / blacklight ~> 8.0 Rails 7.2 / Importmap)	12m 29s
test (ruby 3.3 / rails ~> 8.0 / blacklight ~> 8.0 )	12m 55s
test (ruby 3.2 / rails ~> 8.0 / blacklight ~> 8.0 )	12m 48s
test (ruby 3.4 / rails ~> 8.0 / blacklight ~> 8.0 )	12m 39s
test (ruby 3.3 / rails ~> 7.2 / blacklight ~> 8.0 Rails 7.2 / esbuild)	11m 24s
build	4m 8s
test (ruby 3.2 / rails ~> 8.0 / blacklight ~> 8.0 )	11m 43s
test (ruby 3.3 / rails ~> 8.0 / blacklight ~> 8.0 )	11m 36s
test (ruby 3.3 / rails ~> 7.2 / blacklight ~> 8.0 Rails 7.2 / esbuild)	11m 24s
test (ruby 3.4 / rails ~> 8.0 / blacklight ~> 8.0 )	11m 28s
test (ruby 3.3 / rails ~> 7.2 / blacklight ~> 8.0 Rails 7.2 / Importmap)	12m 29s
	2h 9m 11s

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