feat: added decrementOrCreate to Database Eloquent Builder

[sediqzada94]

Add decrementOrCreate Method to Laravel Eloquent Models

This pull request introduces a new method decrementOrCreate to Laravel's Eloquent Builder. This addition follows the recently merged pull request (#54300) that added the incrementOrCreate method. The decrementOrCreate method provide a straightforward approach to either decrement an existing model's column or create a new model if no existing model matches the provided attributes.

Purpose

The decrementOrCreate method is particularly useful for applications that require decrement operations within their logic, such as inventory management systems where stock levels need to be adjusted down automatically.

Usage Example

The following example demonstrates how to use the decrementOrCreate method in a product inventory scenario:

$product = Product::decrementOrCreate(
    ['name' => 'Laptop'],
    column: 'quantity',
    step: 2,
    extra: [],
);

[shaedrich]

Should there be a check and an exception for when an unsigned column will go below 0 with the attempted decrement?

[taylorotwell]

This is a much less common use case.

[sediqzada94]

Should there be a check and an exception for when an unsigned column will go below 0 with the attempted decrement?

That is logical, but the PR is already closed.