Fix redundant instantiations and uncached reflection in model internals

[techmahedy]

Three performance issues found and fixed in InteractsWithModelQueryProcessing:

1. update() — reflection ran on every call — propertyHasAttribute() creates a ReflectionClass internally. It was called on every update() with no caching, so a model that is updated 100 times in a request paid the reflection cost 100 times.

2. saveMany() — 3 model instances created, only 1 needed — (new static())->propertyHasAttribute(new static(), ...) allocated two extra model instances when the already-created $model variable was sitting right there.

3. getClassProperty() — called deprecated setAccessible() — ReflectionProperty::setAccessible() has been a no-op since PHP 8.1 and triggers a deprecation notice in PHP 8.3. The call was removed.