fix: 修改无法获得服务器全部用户的问题

Flawless.Server/Controllers/AdminController.cs

@@ -39,6 +39,13 @@ public class AdminController(
 
         return user.Admin;
     }
+
+    [HttpGet("user/list")]
+    public async Task<ActionResult<List<AppUser>>> GetUsersAsync()
+    {
+        var users = await userManager.Users.ToListAsync();
+        return users;
+    }
     
     [HttpPost("user/delete/{username}")]
     public async Task<IActionResult> DeleteUserAsync(string username)