Fix Popup card small breakpoint animation

[alanbsmith]

🐛 Bug Report

When a modal is the full height of the viewport, the small breakpoint animation causes the modal to flicker.

To Reproduce

• Visit this example
• Open the modal
• Adjust the viewport size
• Watch it flicker

Expected Behavior

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Actual Results

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Browser (if applicable)

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Link to repl or repo (highly encouraged)

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Error Output

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[mannycarrera4]

No current flickering as of v12