Update Code Suggestions by language chart primary metric

What does this MR do and why?

Switches to Suggestions accepted as the primary metric to avoid misleading rankings from small sample sizes. Also updates the panel title and visualization name, and reorders the tooltip metrics accordingly.

Screenshots or screen recordings

Before	After
Screen Recording 2025-12-11 at 5.03.28 PM.mov	Screen Recording 2025-12-11 at 4.59.00 PM.mov

How to set up and validate locally

1. Please make sure that you're on the GitLab Ultimate plan (if necessary, request a license).
2. Configure your GDK to use ClickHouse
3. Make sure ClickHouse is being used for Analytics by running this in the Rails console: Gitlab::CurrentSettings.current_application_settings.update(use_clickhouse_for_analytics: true)
4. Create a new project or select an existing one.
5. Seed the project using its id in PROJECT_ID=STEP_4_PROJECT_ID FILTER=ai_usage_stats bundle exec rake db:seed_fu
6. Go to the project, then navigate to Analytics Dashboard > GitLab Duo and SDLC trends in the sidebar menu
7. Verify that the chart is rendering correctly*

*If no data is being displayed in the chart, trying changing the visualization's date range:

diff --git a/ee/lib/gitlab/analytics/ai_impact_dashboard/visualizations/code_suggestions_acceptance_rate_by_language_chart.yaml b/ee/lib/gitlab/analytics/ai_impact_dashboard/visualizations/code_suggestions_acceptance_rate_by_language_chart.yaml
index 04a5207ab6ac..5e721e68a5cd 100644
--- a/ee/lib/gitlab/analytics/ai_impact_dashboard/visualizations/code_suggestions_acceptance_rate_by_language_chart.yaml
+++ b/ee/lib/gitlab/analytics/ai_impact_dashboard/visualizations/code_suggestions_acceptance_rate_by_language_chart.yaml
@@ -4,7 +4,7 @@ type: BarChart
 data:
   type: code_suggestions_acceptance_by_language
   query:
-    dateRange: last_30_days
+    dateRange: last_90_days
 options:
   xAxis:
     name: "Acceptance rate"

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #582754