fix: Reraise exceptions in CLI-mode if run in debugger (#225)

## Description
Many exceptions raised by `anemoi-datasets` are of type `ValueError`.
Thus they are caught by `cli_main` and converted to a more user-friendly
error. While this might increase the user experience, it prevents the
use of Python debuggers.

## What problem does this change solve?
Enable the use of debuggers to debug cli runs.

E.g. `ipdb3 $(which anemoi-datasets) create ...`

## What issue or task does this change relate to?

##  Additional notes ##

***As a contributor to the Anemoi framework, please ensure that your
changes include unit tests, updates to any affected dependencies and
documentation, and have been tested in a parallel setting (i.e., with
multiple GPUs). As a reviewer, you are also responsible for verifying
these aspects and requesting changes if they are not adequately
addressed. For guidelines about those please refer to
https://anemoi.readthedocs.io/en/latest/***

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[Contributor License
Agreement.](https://github.com/ecmwf/codex/blob/main/Legal/contributor_license_agreement.md)

Author: MeraX

src/anemoi/utils/cli.py

@@ -265,10 +265,13 @@ def cli_main(
         else:
             cmd.run(args)
     except ValueError as e:
-
         if test_arguments:
             raise
 
+        if sys.excepthook is not sys.__excepthook__:
+            # re-raise exception if non-default excepthook is set (e.g. in pdb)
+            raise
+
         traceback.print_exc()
         LOG.error("\n💣 %s", str(e).lstrip())
         LOG.error("💣 Exiting")