Combine specs for Gitlab::UsageData in EE context

The following discussion from !26296 (merged) should be addressed:

• @dstull started a discussion: (+1 comment)

  This spec file seems like it is out of place...there is already a ee/spec/lib/ee/gitlab/usage_data_spec.rb

  adding these here for now, but as a follow up, these tests should be combined into https://gitlab.com/gitlab-org/gitlab/-/blob/40f5b9b34273af83ee875593a5c002f27e951add/ee/spec/lib/ee/gitlab/usage_data_spec.rb

  unless I'm missing something??

  @a_akgun do you see the same thing?