feat(backend): Deprecate `domain` field in favor of `domains` on SAML connections/account

[NicolasLopes7]

Description

This commit deprecates the existing domain field, and introduces a new domains field on both models:

• SAML connection
• SAML account

It also updates the create and update params to support the new fields

Checklist

• [x] pnpm test runs as expected.
• [x] pnpm build runs as expected.
• [ ] (If applicable) JSDoc comments have been added or updated for any package exports
• [ ] (If applicable) Documentation has been updated

Type of change

• [ ] 🐛 Bug fix
• [x] 🌟 New feature
• [ ] 🔨 Breaking change
• [ ] 📖 Refactoring / dependency upgrade / documentation
• [ ] other:

Summary by CodeRabbit

• New Features

  • Added support for specifying multiple domains in SAML connections via a new domains field.

• Deprecation Notice

  • The existing domain field is now deprecated and will be removed in a future release; users are encouraged to transition to the new domains field.

• Documentation

  • Updated documentation to reflect the deprecation and provide guidance on using the new domains field.