[Bug]: Error messages when loading standard models through Classifier

[alanakbik]

Describe the bug

Loading one of the packaged models using Classifier.load() will cause error messages that a model is not found, even if it is found and loaded.

The problem has become visible through the addition of the PrefixedSequenceTagger class. The loading mechansim in Classifier cycles through all inheriting subclasses (TextClassifier, TokenClassifier, SequenceTagger, etc.), attempts to load the model and if it fails, moves on to the next class. However, some classes output their own error messages, so these are seen by the user.

To Reproduce

from flair.nn import Classifier

tagger = Classifier.load("ner")

Expected behavior

An error message should only be shown if no model can be loaded.

Logs and Stack traces

No response

Screenshots

No response

Additional Context

No response

Environment

Python 3.9,
current master branch