Fix specs to use new template defaults

The default data_category was changed in
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/66076

doc/development/usage_ping/dictionary.md

@@ -4354,6 +4354,8 @@ The total count of Helm packages that have been published.
 
 Group: `group::package`
 
+Data Category: `Optional`
+
 Status: `implemented`
 
 Tiers: `free`, `premium`, `ultimate`

spec/fixtures/lib/generators/gitlab/usage_metric_definition_generator/sample_metric_with_ee.yml

@@ -12,7 +12,7 @@ milestone: "13.9"
 introduced_by_url:
 time_frame: 7d
 data_source:
-data_category: Operational
+data_category: Optional
 distribution:
 - ee
 tier:

spec/fixtures/lib/generators/gitlab/usage_metric_definition_generator/sample_metric_with_name_suggestions.yml

@@ -13,7 +13,7 @@ milestone: "13.9"
 introduced_by_url:
 time_frame: 7d
 data_source:
-data_category: Operational
+data_category: Optional
 distribution:
 - ce
 - ee