accept float (decimal values) directly in multipleOf() rule helper

[mattlibera]

Description

In Laravel, the multipleOf() validation rule accepts integers or decimals. Proper handling decimal values was addressed specifically in a Laravel framework PR after being brought up as a separate issue.

In Filament, the current signature of multipleOf() accepts either int or Closure:

public function multipleOf(int | Closure $value): static
{
    $this->rule(static function (Field $component) use ($value) {
        return 'multiple_of:' . $component->evaluate($value);
    }, static fn (Field $component): bool => filled($component->evaluate($value)));

    return $this;
}

Strictly speaking, this doesn't preclude us from using decimal values here, but doing so requires a Closure:

->multipleOf(fn() => 0.5)

Another workaround would be using rules():

->rules('multiple_of:0.5')

Either of these work just fine by proxying down to the Laravel rule, which validates as expected. Therefore, I am proposing that we also accept float into the multipleOf() helper method. Doing so would preclude the need to work around the issue as above, and also adhere to the way that a developer would be expect to be able to use this helper.

Visual changes

No visual changes included in this PR.

Functional changes

• Code style has been fixed by running the composer cs command.
• Changes have been tested to not break existing functionality.
• Documentation is up-to-date.

No tests currently cover this method, therefore none need modifying.
No documentation currently covers this method in that level of detail, nor do I feel it strictly necessary to call this out in the documentation.

[danharrin]

Thanks!