report traceback on plugin loading for certain verbosities

[jaimergp]

Description

Closes #13742

This is the only way I came up with. Not too clean but not horrible either, I think?

We cannot always pass exc_info because that will muddle the warnings with the traceback. Instead we only do it depending on the verbosity. With -vv (INFO) you'll get the traceback:

# conda info -vv
Error while loading conda entry point: conda-libmamba-solver (name 'AAAY' is not defined)
Traceback (most recent call last):
  File "/workspaces/conda/conda/plugins/manager.py", line 140, in load_entrypoints
    plugin = entry_point.load()
             ^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.12/importlib/metadata/__init__.py", line 205, in load
    module = import_module(match.group('module'))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/conda/lib/python3.12/importlib/__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1310, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 995, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/opt/conda/lib/python3.12/site-packages/conda_libmamba_solver/__init__.py", line 19, in <module>
    AAAY
NameError: name 'AAAY' is not defined

     active environment : base
    active env location : /opt/conda
            shell level : 1
       user config file : /root/.condarc
 populated config files : 
          conda version : 24.1.3.dev120+gbeeaa6fbd
    conda-build version : not installed
         python version : 3.12.2.final.0
                 solver : libmamba (default)
...

With -v or none:

$ conda info -v
Error while loading conda entry point: conda-libmamba-solver (name 'AAAY' is not defined)

     active environment : base
    active env location : /opt/conda
            shell level : 1
       user config file : /root/.condarc
 populated config files : 
          conda version : 24.1.3.dev120+gbeeaa6fbd
    conda-build version : not installed
         python version : 3.12.2.final.0
                 solver : libmamba (default)
...

Checklist - did you ...

• Add a file to the news directory (using the template) for the next release's release notes?
• Add / update necessary tests?
• Add / update outdated documentation?

[codspeed-hq]

CodSpeed Performance Report

Merging #13846 will not alter performance

_{Comparing jaimergp:debug-plugin-loading (8768433) with main (c1af45f)}

Summary

✅ 21 untouched benchmarks

[jezdez]

Needs news and a test if possible

[jezdez]

Nice, exception chaining!