Enable overages warnings for custom roles

What does this MR do and why?

In the group or project member pages, upgrading from minimal or guest access roles to a custom role could incur in additional charges. This MR sends memberRoleId to the gitlabSubscriptionsPreviewBillableUserChange GraphQL endpoint. If the response has a willIncreaseOverage of true it shows the modal asking for confirmation.

Same logic for inviting team members.

EE: true

Screenshots or screen recordings

For the invite members

Screen_Recording_2023-11-29_at_22.50.36

For role promotions to standard roles

Screen_Recording_2023-12-01_at_00.01.09

For role promotions to custom roles

Screen_Recording_2023-12-01_at_15.45.46
Screen_Recording_2023-12-01_at_15.46.43

For inviting guests

Screen_Recording_2023-11-30_at_23.59.31

How to set up and validate locally

1. Enable the following feature flags:

   • echo "Feature.enable(:overage_members_modal)" | gdk rails console
   • echo "Feature.enable(:show_overage_on_role_promotion)" | gdk rails console
   • echo 'Feature.enable(:custom_roles_in_members_page)' | gdk rails console

2. To create a custom role, enable the SaaS simulation and follow these steps.

3. In the member page, assign a custom role to the member. A modal with a warning should be displayed.

4. In the member page, invite a member and assign him/her a custom role. A modal with a warning should be displayed.

5. For local testing if you don't have CustomersDot setup please apply the following change

diff --git a/ee/app/assets/javascripts/invite_members/components/invite_modal_base.vue b/ee/app/assets/javascripts/invite_members/components/invite_modal_base.vue
index e26059e3594b..a7553c341222 100644
--- a/ee/app/assets/javascripts/invite_members/components/invite_modal_base.vue
+++ b/ee/app/assets/javascripts/invite_members/components/invite_modal_base.vue
@@ -216,7 +216,8 @@ export default {
 
       if (this.enabledOverageCheck && !this.willIncreaseOverage && this.hasInput) {
         this.actualFeedbackMessage = '';
-        this.checkEligibility(args);
+        // this.checkEligibility(args);
+        this.checkAndSubmit(args);
       } else {
         this.emitSubmit(args);
       }

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.