Replace deprecated "boolean" with "bool" in PHP code

[arnowelzel]

Description

Since PHP 8.5 using non-canonical type variations, like boolean, in casts is deprecated. Also see https://php.watch/versions/8.5/boolean-double-integer-binary-casts-deprecated.

Related GitHub issue(s)

#7587

Testing instructions

1. Install PODS
2. Use it
3. Verify that there are no warnings about deprecated non-canonical casts

Screenshots / screencast

Changelog text for these changes

All type PHP casts in the form $x = (boolean)$y have been replaced by $x = (bool)$y.

All PHP annotations using boolean as type have been replaced by bool.

PR checklist

• I have tested my own code to confirm it works as I intended.
• My code follows the WordPress Coding Standards.
• My code follows the WordPress Inline Documentation Standards.
• My code includes automated tests for PHP and/or JS (if applicable).