Immutable package warning per TestReferenceImageLibrary asset

• Summary

Building a minimal scene for iOS results in the following Console warning.  

The following asset(s) located in immutable packages were unexpectedly altered. Making changes to immutable packages isn't recommended because the changes can be lost without any warning during Package Manager operations.
  Packages/com.unity.xr.arkit/Tests/Editor/Assets/TestReferenceImageLibrary.asset

Steps to reproduce:

1. 1. Open the attached URP_ARkit project.
   2. Build Settings > iOS > Switch Platform.
   3. Build Settings > Build. 
      Actual results: 

Notice the Console warning.

Expected results: 

Released packages should refrain from throwing Console warnings. 

Reproducible with versions: 

Unity 2022.3.62f1 with ARkit 5.2.0.

Unity 6000.2.5f1 with ARcore 6.2.0.

Not reproducible with versions: 

Can’t test with versions: 

Tested on (OS): 

iOS. 

Notes:

• The repro project is just the Universal Render Pipeline template with ARkit added.  
• Same warning occurs with ARcore; see [Internal link].