Separate EE from SaaS data properly on pipeline_usage_app_data

What does this MR do and why?

This fixes #405173 (closed). The method that provided the data to the frontend was treating all EE data as SaaS data, breaking the UI on Usage Quotas page for Self Managed users.

There's also a small UI improvement on the top title padding for Self Managed, as highlighted in the screenshots below

Screenshots or screen recordings

Before	After	Simulating SaaS

How to set up and validate locally

1. If you have configured your GDK to simulate a SaaS instance make sure to undo it so that your GDK behave as Self-Managed
2. Create a project within a group on a SM instance.
3. Run a pipeline in the project for at least 60 seconds. A single job with sleep 60 should to the trick.
   1. If you don't have runners configured on your local GDK, you can mock the data in the DB:

   # If you already have ci minutes record, update it with any number
   Ci::Minutes::NamespaceMonthlyUsage.where(namespace_id: 188, date: Time.current.utc.beginning_of_month).update(amount_used: 70)
   
   # If you don't have the DB record, create it
   Ci::Minutes::NamespaceMonthlyUsage.new(namespace_id: 188, date: Time.current.utc.beginning_of_month, amount_used: 70).save
   
   # If you want a nice line in the graph, add data for the previous month
   # Create
   Ci::Minutes::NamespaceMonthlyUsage.new(namespace_id: 188, date: Time.current.utc.beginning_of_month - 1.month, amount_used: 50).save
   
   # Update 
   Ci::Minutes::NamespaceMonthlyUsage.where(namespace_id: 188, date: Time.current.utc.beginning_of_month - 1.month).update(amount_used: 50)

4. Go to the top-level group and navigate to: Settins -> Usage Quotas and select the Pipelines tab.
5. Notice how the CI/CD minutes usage quota shows up.

MR acceptance checklist

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