[PM-2799] Add check for api-key on custom plan

[stevefan1999-personal]

Type of change

- [x] Bug fix
- [ ] New feature development
- [ ] Tech debt (refactoring, code cleanup, dependency upgrades, etc)
- [ ] Build/deploy pipeline (DevOps)
- [ ] Other

Objective

There is a bug where custom plan users cannot access the SCIM page of the organization. It may seem like it is a 404 at first glance, but deep down it is actually due to license checking problem. Custom plan organization are implicitly enterprise based anyway.

Code changes

• OrganizationsController.cs: Ignore custom plan for api-key organization

NOTE: As this is a small patch, I did not bother to clone the repo and just edited it on the Github web UI, so I can't do merging, nor do I wish to. Please squash the PR for me instead.

Before you submit

• Please check for formatting errors (dotnet format --verify-no-changes) (required)
• If making database changes - make sure you also update Entity Framework queries and/or migrations
• Please add unit tests where it makes sense to do so (encouraged but not required)
• If this change requires a documentation update - notify the documentation team
• If this change has particular deployment requirements - notify the DevOps team