Fix broken CSS on pipeline graph

What does this MR do?

Reverts MR !40177 (merged)

This allowed a E2E test to pass, but broke some other things (CSS bugs)

The graph was reported to being shifted left here #239446 (closed)

I'm not sure if the permanent fix was delivered, with this CSS being added back the problem with downstream pipeline margin calculations not being applied properly is now fixed.

I'm not seeing the graph shifted left here after applying the CSS back you will find in this MR.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

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