fix(cli): fail CLI script on failed import/export (#16976)

* Test that failing export or import is done properly

For each CLI entry-point we will modify, we make sure that:

- a failing process exits with a non-0 exit code,
- an error is logged.

Signed-off-by: Étienne Boisseau-Sierra <etienne.boisseau-sierra@unipart.io>

* Exit process with error if export/import failed

Bubble exception up when failing import or export

During a CLI import or export of dashboards, if the process fails, the
exception it caught and a simple message is sent to the logger.
This makes that from a shell point of view, the script was successfull —
cf. #16956.

To prevent this, we want to ensure that the process exits with an error
(i.e., a non-0 exit-code) should the export or import fail mid-flight.

Signed-off-by: Étienne Boisseau-Sierra <etienne.boisseau-sierra@unipart.io>