Add tracking for export group members as CSV

In group members UI

app/assets/javascripts/members/components/members_tabs.vue

@@ -113,6 +113,7 @@ export default {
     <template #tabs-end>
       <gl-button
         v-if="shouldShowExportButton"
+        data-event-tracking="click_export_group_members_as_csv"
         class="gl-ml-auto gl-self-center"
         icon="export"
         :href="exportCsvPath"

ee/config/events/click_export_group_members_as_csv.yml

+---
+description: Export group members as CSV
+internal_events: true
+action: click_export_group_members_as_csv
+identifiers:
+- namespace
+- user
+product_group: tenant_scale
+milestone: '17.5'
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/168243
+distributions:
+- ee
+tiers:
+- premium
+- ultimate

ee/config/metrics/counts_28d/count_distinct_user_id_from_click_export_group_members_as_csv_monthly.yml

+---
+key_path: redis_hll_counters.count_distinct_user_id_from_click_export_group_members_as_csv_monthly
+description: Monthly count of unique users that export group members as CSV
+product_group: tenant_scale
+performance_indicator_type: []
+value_type: number
+status: active
+milestone: '17.5'
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/168243
+time_frame: 28d
+data_source: internal_events
+data_category: optional
+distribution:
+- ee
+tier:
+- premium
+- ultimate
+events:
+- name: click_export_group_members_as_csv
+  unique: user.id

ee/config/metrics/counts_7d/count_distinct_user_id_from_click_export_group_members_as_csv_weekly.yml

+---
+key_path: redis_hll_counters.count_distinct_user_id_from_click_export_group_members_as_csv_weekly
+description: Weekly count of unique users that export group members as CSV
+product_group: tenant_scale
+performance_indicator_type: []
+value_type: number
+status: active
+milestone: '17.5'
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/168243
+time_frame: 7d
+data_source: internal_events
+data_category: optional
+distribution:
+- ee
+tier:
+- premium
+- ultimate
+events:
+- name: click_export_group_members_as_csv
+  unique: user.id