Deprecate duplicated icons

Duplicates

These icons were deprecated in Figma library

preview					MR
	arrow-right used 12 times 6.1k instances	long-arrow used 4 times 3.4k instances		Deprecate long-arrow, we don't have any other long- icon, but have arrow- ones	gitlab-org/gitlab!159625 (merged)
	merge-request used 9 times 342k instances	merge-request-open used 5 times 6.3k instance	git-merge used 11 times 1.2k instances	Deprecate merge-request-open and git-merge. Other git icons don't have prefixes and suffixes	gitlab-org/gitlab!159629 (merged) gitlab-org/gitlab!159711 (merged)
	bullhorn used 2 times 38.1k instances	messages used 2 times 3.2k instances		Deprecate messages to avoid confusion between messages and comments	gitlab-org/gitlab!159714 (merged)
	folder 8.3k instances	folder-o used 4 times 37.7k instances		Deprecate folder-o to avoid an icon with suffix and confusion with folder-open	gitlab-org/gitlab!159717 (merged)
	remove used 30+ times 33.7k instances	remove-all used 1 time 484 instances		Deprecate remove-all as less popular	gitlab-org/gitlab!159721 (merged)
	task-done used 2 times 2.7k instances	todo-done used 4 times 220k instances		Deprecate task-done because there are no other task- icons, but there is todo-add icon	gitlab-org/gitlab!159732 (merged)
	dashboard used 2 times 977 instances	tachometer used 0 times 1.6k instances		Deprecate tachometer	tachometer hasn't been used

Icons for consideration

preview
	upload used 7 times 319k instances	export used 3 times 373 instances		Deprecate export as less popular
	download used 22 times 4.2m instances	import used 0 times 93 instances		Deprecate import because it relates to export

Do we need both?

preview	one	two
	approval	approval-solid	We use both, looks like we can't merge them
	attention	attention-solid	We don't use attention-solid
	plus-square	plus-square-o	We don't use plus-square-o
	check-circle	check-circle-filled	We use both, looks like we can't merge them
	information	information-o	We use both, but looks like we can merge them. information-o is more popular. So we can replace information svg with information-o and migrate to information at the end
	question	question-o	Same as for information icon
	image-comment-light	image-comment-dark	We don't use image-comment-light
	file-addition	file-addition-solid	We use both
	file-deletion	file-deletion-solid	We use both
	file-modified	file-modified-solid	We use both

Almost the same

preview	one	two
	location 10.3k instances	location-dot 21.5k instances	Both are used once, we can merge them
	check/16 25.7k instances	mobile-issue-close 10.8k instances	We can deprecate mobile-issue-close
	close/16 808k instances	merge-request-close-m 755 instances	We don't use merge-request-close-m