Pattern Previews: All patterns appear full width, even if they're not full-width

[kjellr]

Describe the bug

All patterns in the directory previews are currently appearing full-width, regardless of their alignment settings. This can be confusing since it's unclear to users which patterns are actually full-width.

For example, all of these appear full-width, but they're actually (from left-to-right) wide, wide, and standard-width:

At some point earlier, we had the option of specifying a viewportWidth in the editor to help with this, but that doesn't appear possible anymore? Is this something we can adjust somehow?

I'm not sure wether to label this as a bug, since it technically works right now. But I think this could definitely be improved.

[ryelle]

I think this was due to the previous theme & editor styles that were loaded, and after #266 this has been fixed. @kjellr let me know if you're still seeing the issue.

[kjellr]

It appears to be fixed. Thanks!