Gutenberg v8.0.0: duplicate Preview links appearing in the header

[andrewserong]

The class name for the Preview dropdown in Gutenberg has been updated as of GB v8.0.0, which results in two Preview links appearing the editor header (change introduced in WordPress/gutenberg#21309):

This should be resolved by updating the line

wp-calypso/apps/wpcom-block-editor/src/calypso/features/legacy-preview-button.scss

Line 15 in 722d1e8

.editor-post-preview__dropdown {

to use the .block-editor-post-preview__dropdown class instead. (To support both GB v7.8.1 and v8.0.0 concurrently, it'd be a good idea to use both selectors).

[ramonjd]

Created #41528 for the heck of it :)