Show all active plugins in Plugin Suppression rather than just those with validation errors detected

[westonruter]

Feature description

Currently the Plugin Suppression section only appears if there are active plugins which have validation errors currently detected (for non-stale validation results). This results in a section that appears and disappears seemingly at random. This can make it difficult for users who know up-front that they will want to suppress a given plugin, as they'll try to find a scenario to cause a validation error for that plugin to be triggered. This is complicated even more for users who don't have developer tools enabled, since at present validation results won't be stored for them (until #1756).

Additionally, the Plugin Suppression section being hidden when the plugin is first activated hurts discoverability for the feature.

So, the Plugin Suppression section should be always displayed and populated with all active plugins, not just the active plugins that have non-stale validation errors associated with them.

Something else to consider: we may want to add a “AMP Suppressed” column to the plugin list table which allows this suppression to be managed from the Plugins screen, in a similar way to how users can manage whether a plugin will auto-update in WordPress 5.5. This would allow for a user to install a plugin and suppress it from being active on AMP pages even before it is first activated. This could also make Plugin Suppression integrate more seamlessly with the rest of WordPress.

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Implementation brief

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Demo

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