useOverlayPosition: user-defined maxHeight is ignored when userSetMaxHeight < maxHeight

# 🙋 Feature Request

I'm working on integrating react-aria into out existing project.

I'm looking for some motivation beneath this decision: https://github.com/adobe/react-spectrum/issues/1500#issuecomment-784033555

It's a common behaviour for us to let users scroll the page if the dropdown with e.g min-height: 300px can't be rendered into viewport. But calculated max-height seems to crop the popup/dropdown to fit the screen.

Although it can be solved either with setting maxHeight bigger that calculated or deleting max-height property from returned styles object, it can't be done that way because of this line: https://github.com/adobe/react-spectrum/blob/273e828cd17c3d229e8ab10ce62bd0a6f0f43963/packages/%40react-aria/overlays/src/useOverlayPosition.ts#L149

Is there any motivation beneath this decision that I'm not taking into consideration. Or can we somehow patch this place (e.g when maxHeight=null or smth like that) to handle this case?

I'm ready to submit a PR but wondering what way is preferred to handle it

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Another dirty dirty hack to overcome this problem is to set `maxHeight: -Infinity`

Start with packages/@react-aria/overlays/src/useOverlayPosition.ts at the behavior around line 149, then read the linked issue for the motivation behind the current decision. Determine the preferred handling when a user-defined maxHeight is smaller than the calculated value, and confirm the resulting overlay sizing behavior before adding coverage for the chosen approach.

Written by the indexing model from the issue text.