Remove unnecessary error message for match class patterns

[cdce8p]

Remove Cannot determine type of ... error for class patterns if the class to match cannot be resolved. In these cases a Name ... is not defined error is already emitted. The captured variable should simply be inferred as Any.

Previously, this was especially an issue for class matches to a class from an untyped library together with a MemberExpr. An example from pylint / astroid which shouldn't emit any errors:

from typing import Any
from astroid import nodes

def func(var: Any) -> None:
    match var:
        case nodes.Assign(targets=t):
            reveal_type(t)  # Any

[github-actions]

Diff from mypy_primer, showing the effect of this PR on open source code:

core (https://github.com/home-assistant/core)
- homeassistant/components/onkyo/media_player.py:354: error: Cannot determine type of "volume"  [has-type]
- homeassistant/components/onkyo/media_player.py:360: error: Cannot determine type of "muting"  [has-type]
- homeassistant/components/onkyo/media_player.py:363: error: Cannot determine type of "source"  [has-type]
- homeassistant/components/onkyo/media_player.py:364: error: Cannot determine type of "source"  [has-type]
- homeassistant/components/onkyo/media_player.py:366: error: Cannot determine type of "source"  [has-type]
- homeassistant/components/onkyo/media_player.py:383: error: Cannot determine type of "sound_mode"  [has-type]
- homeassistant/components/onkyo/media_player.py:384: error: Cannot determine type of "sound_mode"  [has-type]
- homeassistant/components/onkyo/media_player.py:386: error: Cannot determine type of "sound_mode"  [has-type]
- homeassistant/components/onkyo/media_player.py:398: error: Cannot determine type of "hdmi_output"  [has-type]
- homeassistant/components/onkyo/media_player.py:403: error: Cannot determine type of "preset"  [has-type]