RangeControl styling sins

[stokesman]

RangeControl signals interactivity where there is none in two ways. First, its root element sports a cursor:pointer style yet not all of that area is interactive. Second, at each end of the range, half of its Thumb is outside the interactive area, making that half a trap because clicking on it will do nothing (except blur the input if it had focus).

Screen Capture

To reproduce
Steps to reproduce the behavior:

1. Using a cursor-having device, open your nearest Block Editor (maybe: https://wordpress.org/gutenberg/).
2. Add a block with a RangeControl in its settings (Spacer, Columns, Gallery, etc.)
3. Find the RangeControl in block settings
4. Have a go at reproducing the cases previously described

Expected behavior
Any portion of the component that is not interactive should not signal interactivity.

Editor version (please complete the following information):

• WordPress version: 5.5
• Gutenberg: as shipped or with plugin (8.9.2)

[stokesman]

Fixing this is easy enough but I think some feedback could help before making a PR. The route of least change is to widen the range input element by positioning it's left and right edges farther out from the center by half the width of the thumb. It doesn't affect the visual track area just expands the interactive area. However, I think it'd be an improvement to widen the track area and prevent the thumb from sticking out at all. It betters alignment and correspondence of visual track area to interactive area. Here are a couple of screenshots to illustrate:

That is all in regards to the second part of the issue. No debate on the first part, just removal of the cursor:pointer style from the root element.