*Issue:* After adding and removing a spline within a spline container on a prefab (or child object of a prefab), the removed spline will automatically be added back during runtime. This is not the case when the object is not a prefab.

*Steps to reproduce*
* Create a new Unity project
* Import the Splines package
* Create two game objects with spline containers
* Add a spline to each spline container (spline count = 1 in each spline container)
* Make one of these game objects a prefab
* Add an additional spline in both spline containers (spline count = 2 in each spline container)
* Remove the additional spline in both spline containers (spline count = 1 in each spline container)
* Enter play mode
* Observe the spline container component on both game objects

*Expected result*
Both spline containers should contain only 1 spline

*Actual result*
The spline container on the prefab object in the scene has automatically added another spline at runtime. So, the non-prefab object correctly has 1 spline while the prefab object now contains 2.

*Versions tested*
Unity 2022.3.21f1 (Splines 2.5.2), Unity 2022.3.35f1 (Splines 2.6.1), 6000.0.13f1 (Splines 2.6.1)

Video link: [https://drive.google.com/file/d/1w0U7XCa3nMnW-j-XIPWTyY9jtC44LuOx/view]