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>