Support Commutative Property for Q() and Exists() Objects

[archie-ai-code-explain-pr-review]

• The Q() and Exists() objects in Django do not support the commutative property when using the & (and) operator.
• Specifically, the expression Q() & Exists(Product.objects.all()) raises a TypeError, while the expression Exists(Product.objects.all()) & Q() works as expected.
• The error message indicates that the _combine() method in the Q class is not handling the case where the other argument is an Exists object. The method expects the other argument to be a Q object, and it raises a TypeError when it's not.
• To resolve this issue, it would be helpful to have the __rand__ method defined for the Exists class, which would allow the commutative property to work as expected.