Change dataset header floats on top of table entries

[villebro]

Screenshot

Description

When scrolling the change dataset table, the header floats above the table entries. Regression caused by #12432

Design input

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tag accordingly. For design review, add the
label design:review. If this includes a design proposal,
include the label design:suggest]

[junlincc]

Screen.Recording.2021-01-15.at.12.51.27.AM.mov

this behavior is currently not in master and is mentioned in #12503 but yea it would have caused regression without changes made in #12471 going in, thus not including both in v1.0. 🤦🏾‍♀️

[villebro]

Closing as this recording does not reflect current state of master