Working on making Material Editor able to open materials that have missing textures.

Made it a warning instead of an error when MaterialAssetCreator can't find a texture.
Updated the Material Editor's MaterialDocument class to not elevate warnings to errors.
Material Editor uses new features in TraceRecorder to show a message dialog when warnings are detected so the user is notified of the missing texture.

Next I will work on making MaterialAssetCreator put a "missing" texture in place of the requested one.

Signed-off-by: santorac <55155825+santorac@users.noreply.github.com>

Gems/Atom/Tools/AtomToolsFramework/Code/Source/Document/AtomToolsDocumentSystemComponent.cpp

@@ -495,8 +495,6 @@ namespace AtomToolsFramework
             return AZ::Uuid::CreateNull();
         }
 
-        traceRecorder.GetDump().clear();
-
         bool openResult = false;
         AtomToolsDocumentRequestBus::EventResult(openResult, documentId, &AtomToolsDocumentRequestBus::Events::Open, requestedPath);
         if (!openResult)
@@ -507,6 +505,12 @@ namespace AtomToolsFramework
             AtomToolsDocumentSystemRequestBus::Broadcast(&AtomToolsDocumentSystemRequestBus::Events::DestroyDocument, documentId);
             return AZ::Uuid::CreateNull();
         }
+        else if (traceRecorder.GetWarningCount(true) > 0)
+        {
+            QMessageBox::warning(
+                QApplication::activeWindow(), QString("Document opened with warnings"),
+                QString("Warnings encountered: \n%1\n\n%2").arg(requestedPath.c_str()).arg(traceRecorder.GetDump().c_str()));
+        }
 
         return documentId;
     }