Replace client resolvers with API for add-on eligible users

What does this MR do and why?

Replace client resolvers with API for add-on eligible users

• Remove sort option as it is not yet supported (decision here: https://gitlab.com/gitlab-org/gitlab/-/issues/421974#note_1578239332)

Related to #421967

Screenshots or screen recordings

Screen_Recording_2023-10-03_at_4.41.05_PM

How to set up and validate locally

Application setup

1. Customers Dot needs to be setup in order to view the billing page for a group
2. Start GDK in SaaS mode GITLAB_SIMULATE_SAAS=1 gdk start

Group setup

1. Create a Group
2. Buy a Subscription for your group from Settings > Billing

Feature flag

Run the following in your rails console

Feature.enable(:hamilton_seat_management, Namespace.find(your-group-id)

Add-on purchase

Run the following in your rails console

1. Find the namespace

namespace = Namespace.find(your-group-id)

2. Create an Addon

add_on = GitlabSubscriptions::AddOn.find_or_create_by!(name: "code_suggestions") {|e| e.description = "Test"}

3. Create an add-on purchase

GitlabSubscriptions::AddOnPurchase.create!(add_on: add_on, namespace: namespace, expires_on: 1.month.from_now, quantity: 20, purchase_xid: 'A-S0001')

Code Suggestions tab

1. Visit /groups/<your-namespace-name>/-/usage_quotas#code-suggestions-usage-tab

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.