fix: improve error message for plugin

[JeyJeyGao]

Fix:

• Simplified the error message for plugin errors.
• Logged the details of the failing plugin command instead of printing them out in the CLI output, as users may not understand what the plugin command is, which can mislead them about the important part of the error message.
• Logged the error code instead of printing it out in the CLI output to simplify the error message.

Previous example:

notation sign xxx.azurecr.io/hello-app:v1 --plugin azure-kv --id https://xxx.vault.azure.net/certificates --plugin-config credential_type=azurecli 
Warning: Always sign the artifact using digest(@sha256:...) rather than a tag(:v1) because tags are mutable and a tag reference can point to a different artifact than the one signed.
Error: failed to execute the describe-key command for azure-kv: VALIDATION_ERROR: Invalid input passed to "--id". Please follow this format to input the ID "https://<vault-name>.vault.azure.net/certificates/<certificate-name>/[certificate-version]"

Current example:

notation sign xxx.azurecr.io/hello-app:v1 --plugin azure-kv --id https://xxx.vault.azure.net/certificates --plugin-config credential_type=azurecli 
Warning: Always sign the artifact using digest(@sha256:...) rather than a tag(:v1) because tags are mutable and a tag reference can point to a different artifact than the one signed.
Error: failed to sign with the plugin azure-kv: Invalid input passed to "--id". Please follow this format to input the ID "https://<vault-name>.vault.azure.net/certificates/<certificate-name>/[certificate-version]"

Resolves #404
Signed-off-by: Junjie Gao junjiegao@microsoft.com

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.73%. Comparing base (b3b8cbe) to head (a94af32).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #406      +/-   ##
==========================================
- Coverage   80.75%   80.73%   -0.03%     
==========================================
  Files          33       33              
  Lines        2448     2455       +7     
==========================================
+ Hits         1977     1982       +5     
  Misses        331      331              
- Partials      140      142       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[github-actions]

This PR is stale because it has been opened for 45 days with no activity. Remove stale label or comment. Otherwise, it will be closed in 30 days.

[Two-Hearts]

PR needs rebase. Otherwise, LGTM.

[priteshbandi]

LGTM