Primer::Alpha::ToggleSwitch jumps in the small variant

[HDinger]

Steps to reproduce

1. Go to https://view-components-storybook.eastus.cloudapp.azure.com/view-components/lookbook/inspect/primer/alpha/toggle_switch/small
2. Click on the toggle
3. Observe the position of the toggle

Actual behaviour

• The toggle jumps to the top when the loading indicator is shown
• It jumps back after the loading indicator has vanished

Expected behaviour

• There should be no jump

Environment

• Browser: Chrome, Firefox
• Primer version: 0.18.2