[C++][Integration] Enable extension type test with C Data Interface

[pitrou]

Describe the enhancement requested

This TODO deserves fixing:

arrow/dev/archery/archery/integration/datagen.py

Lines 2020 to 2022 in 4592486

	# TODO: ensure the extension is registered in the C++ entrypoint
	.skip_format(SKIP_C_SCHEMA, 'C++')
	.skip_format(SKIP_C_ARRAY, 'C++')

Component(s)

C++, Integration

[pitrou]

Issue resolved by pull request 47888
#47888