Added unit tests for spawnable entity aliases.

This also fixes several issues discovered through the unit tests and renames a few functions to be clearer.

Signed-off-by: AMZN-koppersr <82230785+AMZN-koppersr@users.noreply.github.com>

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Spawnable/PrefabProcessorContext.cpp

@@ -220,7 +220,7 @@ namespace AzToolsFramework::Prefab::PrefabConversionUtils
             if (it == aliasVisitors.end())
             {
                 AzFramework::Spawnable::EntityAliasVisitor visitor = source->m_spawnable.TryGetAliases();
-                AZ_Assert(visitor.HasLock(), "Unable to obtain lock for a newly create spawnable.");
+                AZ_Assert(visitor.IsSet(), "Unable to obtain lock for a newly create spawnable.");
                 it = aliasVisitors.emplace(source->m_spawnable.GetId(), AZStd::move(visitor)).first;
             }
             it->second.AddAlias(

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Spawnable/PrefabProcessorContext.h

@@ -42,7 +42,8 @@ namespace AzToolsFramework::Prefab::PrefabConversionUtils
     {
         NoLoad,         //!< Don't load the spawnable referenced in the entity alias. Loading will be up to the caller.
         QueueLoad,      //!< Queue the spawnable referenced in the entity alias for loading. This will be an async load because asset
-                        //!<    handlers aren't allowed to start a blocking load as this can lead to deadlocks.
+                        //!<    handlers aren't allowed to start a blocking load as this can lead to deadlocks. This option will allow
+                        //!<    to disable loading the referenced spawnable through the event fired from the spawnables asset handler.
         DependentLoad   //!< The spawnable referenced in the entity alias is made a dependency of the spawnable that holds the entity
                         //!<    alias. This will cause the spawnable to be automatically loaded along with the owning spawnable.
     };