<perspective-viewer> UI cleanup

[texodus]

This PR splits some changed from #901 into a stand-alone PR, and the changes were reviewer by @zemeolotu offline. #901 itself has been rebased on top of this PR.

Styling changes:

• Denser active columns in material.dense
• Commas actually on the end of their filter term (instead of the beginning of the next term).
• Less padding on term controls e.g. sort order.
• Removed active tab divider highlights.
• Better inactive tab highlighting when the settings pane is opened.
• Responsive styling now utilizes async resize to reduce redraw tearing.

Misc:

• Fixes clear() error for perspective-viewer #878
• Fixes <perspective-viewer> support for attributes without setters.
• Adds Promise<Table> support to <perspective-viewer>