Verify `overflow-x` utility on `mzp-c-split`

[janbrasna]

Description

protocol/assets/sass/protocol/components/_split.scss

Lines 10 to 11 in d0fd6c5

	.mzp-c-split {
	overflow-x: hidden;

This was added in #675 — and we ended up overriding that on bedrock for causing bugs. Could it be improved, or eventually removed if not necessary in general? (Or it is necessary, and consumers should only tweak that based on particular usage?)

Expected result

mozilla/bedrock#14653

Actual result

mozilla/bedrock#14491
mozilla/bedrock#12848

Success criteria

mozilla/bedrock#12848 (comment)

I see it's there from the beginning of Split component #675 replacing hero/feature w generic block and could't find any mention of it, just this related bit #360 (comment):

"I expected us to have overflow-x:hidden on body but we don't. I assume it's for a good reason.
That means this component needs to safe guard against a crawl bar. I think that means it can't be nested in mzp-l-content."

So it might need a more info from the author whether it's viable to remove in Protocol or the local override for any cropped UI is safer.