refactor/cleanup existing embedded layout implementation

[#41475493]
simplify/dry-up style definitions for Interactives

[#41475493]
size of Interactive: small, medium, large

[#42848537]

Support selecting a small, medium, large size for the
iframe-embedded Interactive in the Interactive Browser.
general method for minimum font-size filtering

[42848537]
apply min font-size filter to popup panes also

[#42848537], [#38376429]