Fix broken FOSS build in import_test_coverage_spec.rb

97f102f4 introduced a fixture that is
only present in EE. When the FOSS build attempt to run this test, it
failed because the file did not exist.

To fix this, we only add this fixture under an EE build.

We also need to mute a FOSS-only failure with `project.issues.events`
because that relation is only tested in the EE-specific fixture.

Closes https://gitlab.com/gitlab-org/gitlab/issues/197298

spec/lib/gitlab/import_export/import_test_coverage_spec.rb

@@ -17,6 +17,7 @@ describe 'Test coverage of the Project Import' do
   # opening a follow-up issue to fix this.
   MUTED_RELATIONS = %w[
     project.milestones.events.push_event_payload
+    project.issues.events
     project.issues.events.push_event_payload
     project.issues.notes.events
     project.issues.notes.events.push_event_payload
@@ -55,13 +56,19 @@ describe 'Test coverage of the Project Import' do
   # Note that we use separate fixture to test ee-only features.
   # Most of the relations are present in `complex/project.json`
   # which is our main fixture.
+  PROJECT_JSON_FIXTURES_EE =
+    if Gitlab.ee?
+      ['ee/spec/fixtures/lib/gitlab/import_export/designs/project.json'].freeze
+    else
+      []
+    end
+
   PROJECT_JSON_FIXTURES = [
     'spec/fixtures/lib/gitlab/import_export/complex/project.json',
     'spec/fixtures/lib/gitlab/import_export/group/project.json',
     'spec/fixtures/lib/gitlab/import_export/light/project.json',
-    'spec/fixtures/lib/gitlab/import_export/milestone-iid/project.json',
-    'ee/spec/fixtures/lib/gitlab/import_export/designs/project.json'
-  ].freeze
+    'spec/fixtures/lib/gitlab/import_export/milestone-iid/project.json'
+  ].freeze + PROJECT_JSON_FIXTURES_EE
 
   it 'ensures that all imported/exported relations are present in test JSONs' do
     not_tested_relations = (relations_from_config - tested_relations) - MUTED_RELATIONS