Like button in is:liked-by-me search results.

[isoos]

• Display the /my-liked-packages page the same way as other package listing. #8887
• Updated like button template: moved the count to the button to make it easier to update labels on page.
• Updated like event handling: works if the like button has no label.
• Updated cache purge when like/unlike happens.
• The like button is only displayed behind experiment and when the search query has is:liked-by-me predicate. Extending it to be a generic button in all listing may be possible, but it may not be needed at all (the button is now a substitute for the unlike button in the /my-liked-packages page).