Infinite Scroll: ensure click handler is removed when IS is rendering the button (default behaviour)

Since the removal is within a click handler, `this` is no longer the proper scope for our needs. As a result, the "load more" button isn't removed and multiple copies will be present on the page. Introduced in r95922.

See #28321-z.

Merges r96156-wpcom.
Infinite Scroll: bump up the default footer width to accommodate longer footer links.

See http://[private link] and r96337.

Merges r96380-wpcom.
Google+ Authorship

Add an option to still enable G+ but hide from display (still adds link attribute to header, etc).

See https://[private link] requested by matt.

Merges r96140-wpcom.
Sharing Buttons

Update size of the smart pinterest button so its not stretched.

Merges r96128-wpcom.
Sharedaddy: Fix oval skew in admin interface for custom buttons with the round option picked. Also allow color icons instead of grasycale, for custom buttons.

Merges r96388-wpcom.
Sharing Buttons

Remove the pin count from the smart button preview. We don't support it anymore.

Merges r96127-wpcom.
Optimize images

Merges r96181-wpcom.
Props wpcom user @optimizerbot.
Widget Customizer: support Widget Visibility (Widget Conditionals)

See #6513.

Merges r96370-wpcom.
Pinking shears

Merges r96371-wpcom.
Merge pull request #492 from Automattic/wpcom-merge-apr23

Wpcom merge apr23