[Multi-Tenant] Add tests to existing tenant services/resolvers

[njlie]

Tests need to be added to features that have been created for mulit-tenancy. Specifically:

Backend:

• /packages/backend/src/tenant/service.test.ts
• /packages/backend/src/tenant/endpoint/service.test.ts
• /packages/backend/src/graphql/resolvers/tenant.test.ts

Auth:

• /packages/auth/src/tenants/service.test.ts
• /packages/auth/src/graphql/resolvers/tenant.test.ts

[njlie]

Closing as current multi-tenancy feature branch implements deprecated design.

[njlie]

Closing again as we are using the original design for multi-tenancy, but are starting fresh.