Fix equality check on property group (#13133)

* Fix equality check on property group

Also fix circular reference on PropertyTypeCollection

(cherry picked from commit f64f634979)

src/Umbraco.Core/Models/PropertyGroup.cs

@@ -2,6 +2,7 @@ using System.Collections.Specialized;
 using System.Diagnostics;
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.Serialization;
+
 using Umbraco.Cms.Core.Models.Entities;
 
 namespace Umbraco.Cms.Core.Models;
@@ -132,7 +133,7 @@ public class PropertyGroup : EntityBase, IEquatable<PropertyGroup>
     }
 
     public bool Equals(PropertyGroup? other) =>
-        base.Equals(other) || (other != null && Type == other.Type && Alias == other.Alias);
+        base.Equals(other) || (other != null && Type == other.Type && Alias == other.Alias && Id == other.Id);
 
     public override int GetHashCode() => (base.GetHashCode(), Type, Alias).GetHashCode();
 

src/Umbraco.Core/Models/PropertyTypeCollection.cs

@@ -30,7 +30,7 @@ public class PropertyTypeCollection : KeyedCollection<string, IPropertyType>, IN
     // This baseclass calling is needed, else compiler will complain about nullability
 
     /// <inheritdoc />
-    public bool IsReadOnly => ((ICollection<IPropertyType>)this).IsReadOnly;
+    public bool IsReadOnly => false;
 
     // 'new' keyword is required! we can explicitly implement ICollection<IPropertyType>.Add BUT since normally a concrete PropertyType type
     // is passed in, the explicit implementation doesn't get called, this ensures it does get called.