Raise a generic exception in CiConfiguration::BaseCreateService

What does this MR do and why?

This merge request updates:

• Types::ProjectType
• Security::CiConfiguration::BaseCreateService

To do the following respectively:

• Remove the use of to_user_facing utility method as per the discussion in #416434 (comment 1450977807).
• Raise a generic exception as MutationError exception is is not very descriptive of the error or exception.

Resolves #393703 (closed).

MR acceptance checklist

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• I have evaluated the MR acceptance checklist for this MR.