[9.x] Add withoutForeignKeyConstraints() to disable foreign key constraints in a callback

[phh]

If you want to disable foreign key constraints today you:

Schema::disableForeignKeyConstraints();

Schema::dropIfExists('table1');
Schema::dropIfExists('table2');

Schema::enableForeignKeyConstraints();

My suggestion is to add this in a callback instead of remembering to disable and enable again afterwards:

Schema::withoutForeignKeyConstraints(function () {
    Schema::dropIfExists('table1');
    Schema::dropIfExists('table2');
});

I've not added tests, since I could not find any for disableForeignKeyConstraints() and enableForeignKeyConstraints(). If this idea is something that is interesting I could look into how to add tests for it.