Check nil before checking connection

What does this MR do?

• Updates AuthorizeFieldService to check if the resolved type is nil before attempting to authorize a connection field

When the field is a connection using a resolver but the resolved type is nil, the connection field logic tries to call object on nil and throws a NoMethodError. By checking if the resolved type is nil first, we avoid this issue.

Issue #214047 (closed)

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. l, or other methods