Draft: chore(GlBadge): Add story for baseline alignment

What does this MR do?

fix(GlBadge): Ensure consistent baseline

Previously, the text-only type of GlBadge did not share the same baseline as the icon-only and icon-and-text versions.

This is because GlBadge's icons are set to a height of 16px, whereas the line-height of the text is 14px. Combined with .gl-badge's styling of align-items: center, this made the icon determine the badge's baseline, rather than the text.

The fix is to make sure that the text determines the baseline. For the icon-and-text case, that's straight forward: set align-items: baseline for the .gl-badge, and set the icon to align-self: center.

The icon-only case is trickier, since there is no text to create a baseline from. The fix in this case is also simple, but weird: to add a .gl-badge::after pseudo element with the content of a zero-width space!

It must be a zero-width space so that it doesn't affect the rendered output, other than creating the text baseline if there isn't any other text.

Addresses #1673 (closed).

Screenshots

	Screenshot
Before MISALIGNED
After, without pseudo element fix MISALIGNED
After, with pseudo element and regular space MISALIGNED
Final result, with pseudo element and zero-width space (this MR) ALIGNED

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Closes #1673 (closed)