Ensure GraphQL SSO Enforcement test can fail

What

Ensures that tests in !21922 (merged) can fail if the session is not set.

Results in the following if skip_around_action :set_session_storage is removed from GraphqlController:

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3 examples, 2 failures

Failed examples:

rspec ./ee/spec/requests/api/graphql/group_query_spec.rb:32 # getting group information Query group(fullPath) when Group SSO is enforced allows access via session
rspec ./ee/spec/requests/api/graphql/group_query_spec.rb:39 # getting group information Query group(fullPath) when Group SSO is enforced allows access via bearer token

Why

Discovered in !29845 (merged) where a related fix should have caused failures here