Remove the `apiFuzzingCiConfigurationCreate.configurationYaml` GraphQL field

Why are we doing this work

In #333233 (closed), we have deprecated apiFuzzingCiConfigurationCreate.configurationYaml which was not needed anymore as we've decided to move the snippet's generation to the frontend. When at least 6 releases have passed, and the deprecation has been announced properly following the breaking changes process, we should remove the field altogether

Relevant links

• Prior art

Non-functional requirements

• Documentation:
• Feature flag:
• Performance:
• Testing:

Implementation plan

• Remove the apiFuzzingCiConfigurationCreate.configurationYaml and all of the associated specs.