typecheck/Enum: fix crash in Enum attributes check

[huwcbjones]

Type of Changes

	Type
✓	🐛 Bug fix

Description

Fixes #6805 by:

• only checking for Enum attributes when metaclass is an Enum metaclass
• coping with a name not being returned in __new__

[coveralls]

Pull Request Test Coverage Report for Build 2444476621

• 4 of 4 (100.0%) changed or added relevant lines in 1 file are covered.
• 65 unchanged lines in 6 files lost coverage.
• Overall coverage increased (+0.009%) to 95.53%

---

Files with Coverage Reduction	New Missed Lines	%
pylint/checkers/modified_iterating_checker.py	2	97.56%
pylint/config/arguments_manager.py	2	98.22%
pylint/lint/message_state_handler.py	4	96.55%
pylint/checkers/refactoring/refactoring_checker.py	12	98.39%
pylint/checkers/variables.py	22	96.61%
pylint/lint/pylinter.py	23	94.9%

Totals
Change from base Build 2433586834:	0.009%
Covered Lines:	16329
Relevant Lines:	17093

---

💛 - Coveralls

[jacobtylerwalls]

Thanks for the speedy work. Needs a short release note in 2.14/full.rst

[jacobtylerwalls]

Outside the scope of this PR, since status quo, but this looks fragile against importing enum under an alias, which @DanielNoord was just looking into at pylint-dev/astroid#1587. Probably worth a follow-up issue.

[DanielNoord]

Yeah, we should probably revisit this when we bump to 2.12.

[github-actions]

🤖 Effect of this PR on checked open source code: 🤖

Effect on pytest:
The following messages are now emitted:

1. redefined-variable-type:
   Redefinition of ret type from str to _pytest.config.ExitCode
   https://github.com/pytest-dev/pytest/blob/main/src/_pytest/pytester.py#L1145
2. redefined-variable-type:
   Redefinition of ret type from int to _pytest.config.ExitCode
   https://github.com/pytest-dev/pytest/blob/main/src/_pytest/pytester.py#L1429

This comment was generated for commit 6c9bcbb