Add modal to Buy minutes button

What does this MR do and why?

Add modal to Buy storage button

Call CustomersPortal API to know define if we show a modal for ramp/reseller subscriptions when customer clicks the button.

Criteria to show the modal:

• limited_access_modal FF is ON
• ramp or reseller subscription (in this case API returns canAddSeats: false). We rely on this field even though we add not seats but minutes.

We have this modal already implemented for Add seats button !131533 (merged) and Buy Storage !131695 (merged)

Related to #409750 (closed)

Screenshots or screen recordings

Screen_Recording_2023-10-09_at_21.37.28

How to set up and validate locally

• Create a ramp subscription
• Create a reseller subscription
• Create a subscription without either reseller or ramp attributes
• Run rails c and then `Feature.enable(:limited_access_modal)

For both ramp + reseller subscriptions:

• Link it to a GL namespace either in the CDot UI (subscriptions/SUBSCRIPTION_NAME/edit?transaction=change_gitlab_group) or via the rails console
• In GL, navigate to /groups/GROUP_NAME/-/usage_quotas#pipelines-quota-tab
• Verify that Buy additional compute minutes button appears as usual
• Verify that clicking the button displays the modal and it has a different text for RAMP and RESELLER
• Verify that closing out of the modal functions properly

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.