Improve error handling for fetching API fuzzing scan profiles

Context

The API fuzzing scan profiles are loaded into the API fuzzing CI configuration form by importing them directly from https://gitlab.com/gitlab-org/security-products/analyzers/api-fuzzing/-/raw/master/gitlab-api-fuzzing-config.yml.

Errors in the request are caught and return an empty array. Errors from parsing the YAML are not caught. As a result, no useful error is returned by the scanProfiles field on CiConfiguration::ApiFuzzing::Type.

Proposal

Handle both types of error by returning a GraphQL error detailing the problem. If necessary, update the frontend to respond appropriately to the errors (probably by retrying the query).

Implementation Plan

backend

TBD

frontend

• Add errors to api_fuzzing_ci_configuration.query.graphql
• Implement error handler in the component
• show an alert with error message
• add specs