fix(table): sort indicators backwards

[mcalmus]

Changes the sort arrows so sort ascending points up and sort descending points down.

Fixes #6198

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[jeremyrans]

@mcalmus Do you plan on signing the CLA so we can get this merged?

[mcalmus]

Sorry. I've signed it now.

[googlebot]

CLAs look good, thanks!

[andrewseguin]

Out of date, check out #6802 for an updated version that also improves the animation

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