Remove constructs that deprecate with PHP 8.4

[MarkusBauer]

PHP 8.4 deprecates type declarations of the form function x(string $y = null) - see longer explanation here. PHP 9 will no longer support such implicit nullable parameters.
This PR fixes this pattern everywhere.

How to reproduce: run a syntax check with PHP 8.4:
find . -type f \( -name "*.php" -o -name "*.ctp" \) -exec php -d error_reporting=32765 -l {} \; | grep -v 'No syntax errors detected'
Result before this PR:

PHP 8.4.0alpha2 (cli) (built: Jul 19 2024 19:23:28) (NTS)
Deprecated: ControllerAuthorize::controller(): Implicitly marking parameter $controller as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Controller/Component/Auth/ControllerAuthorize.php on line 46
Deprecated: BaseAuthorize::controller(): Implicitly marking parameter $controller as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Controller/Component/Auth/BaseAuthorize.php on line 92
Deprecated: SecurityComponent::blackHole(): Implicitly marking parameter $exception as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Controller/Component/SecurityComponent.php on line 347
Deprecated: AuthComponent::isAuthorized(): Implicitly marking parameter $request as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Controller/Component/AuthComponent.php on line 456
Deprecated: PrivateActionException::__construct(): Implicitly marking parameter $previous as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Error/exceptions.php on line 300
Deprecated: DboSource::lastError(): Implicitly marking parameter $query as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Model/Datasource/DboSource.php on line 530
Deprecated: DboSource::conditions(): Implicitly marking parameter $Model as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Model/Datasource/DboSource.php on line 2764
Deprecated: DboSource::conditionKeysToString(): Implicitly marking parameter $Model as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Model/Datasource/DboSource.php on line 2807
Deprecated: DboSource::_parseKey(): Implicitly marking parameter $Model as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Model/Datasource/DboSource.php on line 2912
Deprecated: DboSource::order(): Implicitly marking parameter $Model as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Model/Datasource/DboSource.php on line 3086
Deprecated: DboSource::group(): Implicitly marking parameter $Model as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Model/Datasource/DboSource.php on line 3169
Deprecated: DboSource::having(): Implicitly marking parameter $Model as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Model/Datasource/DboSource.php on line 3199
Deprecated: Model::validator(): Implicitly marking parameter $instance as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/Model/Model.php on line 3916
Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /app/lib/Cake/Console/Command/Task/FixtureTask.php on line 251
Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /app/lib/Cake/Console/Command/Task/FixtureTask.php on line 251
Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /app/lib/Cake/Console/Command/Task/ModelTask.php on line 173
Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /app/lib/Cake/Console/Command/Task/ModelTask.php on line 904
Deprecated: Using ${var} in strings is deprecated, use {$var} instead in /app/lib/Cake/Test/Case/Console/ShellTest.php on line 610
Deprecated: XmlView::__construct(): Implicitly marking parameter $controller as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/View/XmlView.php on line 68
Deprecated: JsonView::__construct(): Implicitly marking parameter $controller as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/View/JsonView.php on line 68
Deprecated: View::__construct(): Implicitly marking parameter $controller as nullable is deprecated, the explicit nullable type must be used instead in /app/lib/Cake/View/View.php on line 333

With this PR, the upcoming syntax errors are fixed.

[kamilwylegala]

Shouldn't we keep Controller?

[MarkusBauer]

Yes, $controller is not optional, my bad. Thank you!
(and I also corrected a typo that I just spotted)

[kamilwylegala]

Thanks for fix 🙌

[kamilwylegala]

Thank you for your contribution. I left one comment.

[kamilwylegala]

Looks good, thanks one more time for your contribution. Merging 😊