[BUG] Tethys install command fails when libmamba is set to default solver

[swainn]

Describe the bug The tethys install command fails when libmamba solver is set as default (conda config --set solver libmamba).

To Reproduce Steps to reproduce the behavior:

1. Install libmamba solver and set as default solver per these directions: https://www.anaconda.com/blog/a-faster-conda-for-a-growing-community/
2. Try to install an app in Tethys

Expected behavior It should install using libmamba or at least not fail if that isn't possible.

Errors/Traceback

```bash tethys install -d Installing dependencies... Running conda installation tasks... Retrieving notices: ...working... done Traceback (most recent call last): File "/home/tethysdev/miniconda3/envs/tethys/bin/tethys", line 8, in sys.exit(tethys_command()) ^^^^^^^^^^^^^^^^ File "/home/tethysdev/tethys/tethys_cli/__init__.py", line 67, in tethys_command args.func(args) File "/home/tethysdev/tethys/tethys_cli/install_commands.py", line 750, in install_command install_packages( File "/home/tethysdev/tethys/tethys_cli/install_commands.py", line 680, in install_packages [resp, err, code] = conda_run( ^^^^^^^^^^ File "/home/tethysdev/miniconda3/envs/tethys/lib/python3.11/site-packages/conda/cli/python_api.py", line 118, in run_command raise e File "/home/tethysdev/miniconda3/envs/tethys/lib/python3.11/site-packages/conda/cli/python_api.py", line 107, in run_command result = do_call(args, p) ^^^^^^^^^^^^^^^^ File "/home/tethysdev/miniconda3/envs/tethys/lib/python3.11/site-packages/conda/cli/conda_argparse.py", line 122, in do_call return getattr(module, func_name)(args, parser) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/tethysdev/miniconda3/envs/tethys/lib/python3.11/site-packages/conda/notices/core.py", line 116, in wrapper return_value = func(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^ File "/home/tethysdev/miniconda3/envs/tethys/lib/python3.11/site-packages/conda/cli/main_install.py", line 20, in execute install(args, parser, 'install') File "/home/tethysdev/miniconda3/envs/tethys/lib/python3.11/site-packages/conda/cli/install.py", line 248, in install solver_backend = context.plugin_manager.get_cached_solver_backend() ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/home/tethysdev/miniconda3/envs/tethys/lib/python3.11/site-packages/conda/plugins/manager.py", line 149, in get_solver_backend raise CondaValueError( conda.exceptions.CondaValueError: You have chosen a non-default solver backend (libmamba) but it was not recognized. Choose one of: classic ```

Screenshots N/A

Tethys Environment Information Include output from these commands:

• tethys version
• conda info
• conda list

Additional context Add any other context about the problem here.

[swainn]

This appears to be an issue with conda libmamba solver package's support for the Python API. Posted an issue: https://github.com/conda/conda-libmamba-solver/issues/202