Resizable spaces on opposite sides don't behave like they're on the same layer

[BenJenkinson]

Description:
I am able to drag the edge of a <Space.LeftResizable> past the edge of a <Space.RightResizable> meaning that the content of the left space is underneath the right space (or vice versa)

Example:
An example can be seen on the first "Resizable Spaces" example , here: https://www.allaneagle.com/projects/react-spaces/examples#resizable

To reproduce:

1. Drag the edge of the <Space.LeftResizable> to the right, past the boundary with the <Space.RightResizable>
2. See that the content of the left space is stretched since the left space extends past the boundary, and "underneath" the right space.

Expected behavior:

• I would expect the edge being dragged to "hit" the edge of the other space and then either:
  • ...continue shrinking the right space (according to the right space's minimum size)
  • ...stop (if the right space has a fixed size or is already at its minimum size)
• I would not expect to be able to make one space overlap another space

Screenshots:
Here you can see the overlap between the two spaces where I was able to drag one space border over the other one, despite them being on the same layer.

(I used slightly translucent backgrounds for the two spaces to make it more obvious)

Desktop:

• OS: Windows
• Browser: Chrome
• Version: 83.0.4103.61

Package:

• Version: 0.1.25