Bug Description

In Transitional/Reader modes, there is an AMP preview button that is separate from the regular Preview button. Additionally, as of #5589 there is a new plugin sidebar for displaying validation errors. When that sidebar is pinned, the result is an apparent duplication of the AMP buttons in the toolbar:

Granted we want to eliminate the separate AMP preview button in favor of adding an AMP item to the Preview dropdown, but this is blocked by WordPress/gutenberg#25309. Nevertheless, I wanted to point it out as a potential source of user confusion in the meantime.

The resolution for this issue may be wontfix.

Expected Behaviour

The AMP logo should not appear multiple times in the toolbar.

Steps to reproduce

1. Activate Reader or Transitional mode.
2. Edit a post.
3. Pin the AMP plugin sidebar
4. See two logos in the toolbar

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Acceptance criteria

Implementation brief

QA testing instructions

Demo

Changelog entry