[RUN AS-IF-FOSS] Resolve deprecate cop_helper exceptions part 4

What does this MR do?

• Deprecates/Replaces the use of CopHelper methods as alerted by the Rubocop Cop.
• Remove the redundant require of rubocop/rspec/support as it is already loaded in spec/support/rspec.rb through the require 'fast_spec_helper'
• Prefer matching spelling of offense with rubocop helper naming instead of offence.
• Adheres to the cop that denies that use of described_class::MSG
• Removes unneeded copy name check as message check is unique enough to validate correct cop.
• Prefer frozen_string_literal instead of .freeze when needed.

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

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related to #276734