[widgets][editor] Show error message on new asset creation failure

For example, if a default Algorithm can't be constructed because the
prefix used lacks the reference datformats, show the exception message
rather than make the application crash.
2 jobs for implement_asset_creation in 21 minutes and 40 seconds (queued for 4 seconds)
Status Name Job ID Coverage
  Build
passed build_linux_36 #164806
docker-build

00:05:36

passed build_macosx_36 #164807
macosx

00:21:40