Extend the scope of Graphql/JSONType rubocop

What does this MR do?

This change extends the GraphQL/JSONType to check for offenses in mutations and resolvers.

Previously it was limited to detecting offenses only in types.

See !38125 (comment 389671877)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• [-] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done