[BUG] Custom inspectors for systems and entities are broken

[JesseTG]

Describe the bug

Various custom inspectors are broken, as shown in the attached screenshots.

Unity Version:
Unity 2023.1.5f1

To Reproduce
Steps to reproduce the behavior:

1. Open any scene in which entities and systems are used
2. Select their associated objects in the hierarchy
3. Look at the inspector

Expected behavior

The custom inspectors should render without issues.

Screenshots

Additional context

Here are some relevant exceptions:

[Exception] NullReferenceException: Object reference not set to an instance of an object
GUILayoutUtility.DoGetRect() at <1b7ba2395c4741668d0e335ad4e651c7>:0
GUILayoutUtility.GetRect() at <1b7ba2395c4741668d0e335ad4e651c7>:0
GUILayout.DoTextField() at <1b7ba2395c4741668d0e335ad4e651c7>:0
GUILayout.TextField() at <1b7ba2395c4741668d0e335ad4e651c7>:0
EditorGUILayoutTools.SearchTextField() at ./Library/PackageCache/com.jeffcampbellmakesgames.entitasredux@2.1.4/Scripts/Editor/Tools/EditorGUILayoutTools.cs:148
EntityDrawer.DrawComponents() at ./Library/PackageCache/com.jeffcampbellmakesgames.entitasredux@2.1.4/Scripts/Editor/Inspector/Entity/EntityDrawer.cs:340
EntityDrawer.DrawEntity() at ./Library/PackageCache/com.jeffcampbellmakesgames.entitasredux@2.1.4/Scripts/Editor/Inspector/Entity/EntityDrawer.cs:216
EntityLinkInspector.OnInspectorGUI() at ./Library/PackageCache/com.jeffcampbellmakesgames.entitasredux@2.1.4/Scripts/VisualDebugging/Editor/EntityLinkInspector.cs:63
InspectorElement+<>c__DisplayClass72_0.<CreateInspectorElementUsingIMGUI>b__0() at <8bcfff76472c48f096bf077900dc8a3a>:0
GUIUtility.ProcessEvent()

[Exception] ArgumentException: Getting control 0's position in a group with only 0 controls when doing repaint
Aborting
GUILayoutGroup.GetNext() at <1b7ba2395c4741668d0e335ad4e651c7>:0
GUILayoutUtility.DoGetRect() at <1b7ba2395c4741668d0e335ad4e651c7>:0
GUILayoutUtility.GetRect() at <1b7ba2395c4741668d0e335ad4e651c7>:0
GUILayout.DoTextField() at <1b7ba2395c4741668d0e335ad4e651c7>:0
GUILayout.TextField() at <1b7ba2395c4741668d0e335ad4e651c7>:0
EditorGUILayoutTools.SearchTextField() at ./Library/PackageCache/com.jeffcampbellmakesgames.entitasredux@2.1.4/Scripts/Editor/Tools/EditorGUILayoutTools.cs:148
EntityDrawer.DrawComponents() at ./Library/PackageCache/com.jeffcampbellmakesgames.entitasredux@2.1.4/Scripts/Editor/Inspector/Entity/EntityDrawer.cs:340
EntityDrawer.DrawEntity() at ./Library/PackageCache/com.jeffcampbellmakesgames.entitasredux@2.1.4/Scripts/Editor/Inspector/Entity/EntityDrawer.cs:216
EntityLinkInspector.OnInspectorGUI() at ./Library/PackageCache/com.jeffcampbellmakesgames.entitasredux@2.1.4/Scripts/VisualDebugging/Editor/EntityLinkInspector.cs:63
InspectorElement+<>c__DisplayClass72_0.<CreateInspectorElementUsingIMGUI>b__0() at <8bcfff76472c48f096bf077900dc8a3a>:0
GUIUtility.ProcessEvent()