Pass $attr through to wp_get_attachment_link filter

[danielbachhuber]

The $attr variable is useful context for knowing where wp_get_attachment_link() is being called and, subsequently, how the value should be filtered.

[joemcgill]

@danielbachhuber – Assuming this enhancement still helpful, the patch looks good to me.

[pento]

In 44471:

Media: Add $attr to the wp_get_attachment_link filter.

Props danielbachhuber.
Fixes #40155.