Remove escaping when converting EasyBuildError to a string

[Flamefire]

This is especially useful for Pytorch tests where the error message contains formatted output which becomes hard to read:

== FAILED: Installation ended unsuccessfully: An error was raised during test step: 'Failing because not all failed tests could be determined. Tests failed to start, crashed or the test accounting in the PyTorch EasyBlock needs updating!\nMissing: distributed/test_c10d_nccl\nYou can check the test failures (in the log) manually and if they are harmless, use --ignore-test-failure to make the test step pass.\n109 test failures, 0 test errors (out of 262294):\nFailed tests (suites/files):\n\tdistributed/test_symmetric_memory (23 failed, 20 passed, 1 skipped, 0 errors)\n\tdynamo/test_misc (1 failed, 539 passed, 12 skipped, 0 errors)\n\tdynamo/test_utils (1 failed, 7 passed, 0 skipped, 0 errors)\n\tinductor/test_codecache (1 failed, 110 passed, 3 skipped, 0 errors)\n\tinductor/test_cudacodecache (3 failed, 0 passed, 0 skipped, 0 errors)\n\tinductor/test_cutlass_backend (39 failed, 1 passed, 2 skipped, 0 errors)\n\tinductor/test_fp8 (40 failed, 149 passed, 72 skipped, 0 errors)\n\tinductor/test_torchinductor_dynamic_shapes (1 failed, 1527 passed, 71 skipped, 0 errors)\nCould not count failed tests for the following test suites/files:\n\tdistributed/test_c10d_nccl (Undetected or did not run properly)' (took 64 hours 17 mins 9 secs)

[boegel]

Hmm, there must have been a reason why we did this...

[Flamefire]

C&P from some other code I'd say as this was introduced by renaming some other exception class in the very beginning: https://github.com/easybuilders/easybuild-framework/blame/d7f1ad2f6f09e387e121c94c9df434a07e7aaa68/easybuild/tools/buildLog.py

There is a __repr__ special method that should likely be implemented like that.

Someone notes at https://stackoverflow.com/questions/1436703/what-is-the-difference-between-str-and-repr

default for __repr__ which would act like:

return "%s(%r)" % (self.__class__, self.__dict__)

__repr__ goal is to be unambiguous
__str__ goal is to be readable
This means, in simple terms: almost every object you implement should have a functional __repr__ that’s usable for understanding the object. Implementing __str__ is optional: do that if you need a “pretty print” functionality (for example, used by a report generator).
Summary

Implement __repr__ for any class you implement. This should be second nature. Implement __str__ if you think it would be useful to have a string version which errs on the side of readability.

E.g.

def __repr__(self):
    return f'EasyBuildError({self.msg!r}, {self.exit_code})'