Handles not found errors with more suggestions

[vsantwana]

Release Notes

Breaking Changes

• PLACEHOLDER

New Features

• PLACEHOLDER

Bug Fixes

• Improve error messages for confluent flink application and confluent flink environment commands

Checklist

• [ ] Leave this box unchecked if features are not yet available in production

What

Till now, for the following API calls:

• Delete environment/Delete Application
• Update environment/Update application
• Forward web-ui We used to give not found even if it has any other issue. This PR handles those case and gives more info about the error

Since the delete API depends on the existence check same as other commands, we haven't changed the behaviour there, just that we have added another line of suggestion to the error:

Error: Flink application "default-application-1" not found

Suggestions:
    List available Flink applications with `confluent flink application list`.
    Check that CMF is running and accessible.

In case of connectivity issues with CMF:

> go run cmd/confluent/main.go flink environment update ralo
Error: failed to update environment "ralo": Get "http://localhost:8080/cmf/api/v1/environments/ralo": dial tcp [::1]:8080: connect: connection refused

References

Test & Review

[confluent-cla-assistant[bot]]

:tada: All Contributor License Agreements have been signed. Ready to merge.
_{Please push an empty commit if you would like to re-run the checks to verify CLA status for all contributors.}