feat(server): support installable license (#12181)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **New Features**
  - Added support for installing self-hosted team licenses via encrypted license files.
  - Introduced a new "Onetime" license variant for self-hosted environments.
  - Added a GraphQL mutation to upload and install license files.
  - License details now display the license variant.

- **Bug Fixes**
  - Improved error messages for license activation and expiration, including dynamic reasons.

- **Localization**
  - Updated and improved license-related error messages for better clarity.

- **Tests**
  - Added comprehensive end-to-end tests for license installation scenarios.

- **Chores**
  - Enhanced environment variable handling and public key management for license verification.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/core/workspaces/service.ts

@@ -257,6 +257,11 @@ export class WorkspaceService {
       workspaceId,
       quantity
     );
+
+    if (!pendings.length) {
+      return;
+    }
+
     const owner = await this.models.workspaceUser.getOwner(workspaceId);
     for (const member of pendings) {
       try {