[D7 PHP 8.1] html_entity_decode(): Passing null to parameter #1 ($string) of type string is deprecated in decode_entities()

Looks good.
The patch covers really important things to support PHP 8.1 on D7.

I think this looks good. This code

var_dump(html_entity_decode(NULL, ENT_QUOTES, 'UTF-8'));

in PHP 8.3, 8.2, 8.1 results in:

Deprecated: html_entity_decode(): Passing null to parameter #1 ($string) of type string is deprecated
string(0) ""

and in PHP 7.4, 7.3 and lower in:

string(0) ""

So by casting to string we will keep the same behavior of this function - an empty string will be returned without a deprecation message.

I have added a NULL value to the existing tests. Seems like all pipelines are green (https://git.drupalcode.org/project/drupal/-/pipelines/59079), so adding a tag for the final review. Here is a test-only test which failed as expected: https://git.drupalcode.org/project/drupal/-/jobs/434910. Thanks.

RTBC

Thanks everybody!

Automatically closed - issue fixed for 2 weeks with no activity.