Allow customizing order for AuditingEntityCallback and ValidatingEntityCallback

[yangchef1]

Hi @mp911de, as suggested in #4914, I've submitted a PR to address the issue.
Let me know if there's anything you'd like me to adjust or improve. Thanks!

Allow customizing order for AuditingEntityCallback and ValidatingEntityCallback.
Added corresponding test cases for this functionality.

Closes #4914

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