### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### The Feature

Remove the 5-user limit from the Standard Plan for SSO users. Allow unlimited SSO login accounts on the Standard Plan.

### Motivation, pitch

We are positively considering adopting LiteLLM. Most companies already operate a centralized employee SSO tenant, so integrating SSO is a natural requirement for security and access management.

However, the current 5-user limitation on SSO in the Standard Plan creates a major barrier during the adoption and evaluation process. It makes it difficult for organizations to test LiteLLM in a realistic internal environment across multiple teams and stakeholders.

Someone had to say this. We are likely not the only team facing this issue. Many others are probably already exploring workarounds such as OAuth 2.0 Proxy and similar approaches just to bypass the SSO user cap. It would be much better to simplify this and remove the need for that kind of unnecessary engineering effort and energy waste.

For self-hosted LiteLLM, it would be much better if SSO itself were not restricted in this way. Lowering this barrier …