Fix compile errors with new Vala

[lenemter]

../src/Services/Device.vala:28:36-28:45: error: `owned' accessor not allowed for specified property type
   28 |     public abstract bool blocked { owned get; set; }
      |                                    ^~~~~~~~~~       
../src/Services/Device.vala:29:38-29:47: error: `owned' accessor not allowed for specified property type
   29 |     public abstract bool connected { owned get; }
      |                                      ^~~~~~~~~~  
../src/Services/Device.vala:30:43-30:52: error: `owned' accessor not allowed for specified property type
   30 |     public abstract bool legacy_pairing { owned get; }
      |                                           ^~~~~~~~~~  
../src/Services/Device.vala:31:35-31:44: error: `owned' accessor not allowed for specified property type
   31 |     public abstract bool paired { owned get; }
      |                                   ^~~~~~~~~~  
../src/Services/Device.vala:32:36-32:45: error: `owned' accessor not allowed for specified property type
   32 |     public abstract bool trusted { owned get; set; }
      |                                    ^~~~~~~~~~       
../src/Services/Device.vala:33:34-33:43: error: `owned' accessor not allowed for specified property type
   33 |     public abstract int16 RSSI { owned get; }
      |                                  ^~~~~~~~~~  
../src/Services/Device.vala:40:41-40:50: error: `owned' accessor not allowed for specified property type
   40 |     public abstract uint16 appearance { owned get; }
      |                                         ^~~~~~~~~~  
../src/Services/Device.vala:41:37-41:46: error: `owned' accessor not allowed for specified property type
   41 |     public abstract uint32 @class { owned get; }
      |                                     ^~~~~~~~~~  
../src/Services/Transfer.vala:25:35-25:44: error: `owned' accessor not allowed for specified property type
   25 |     public abstract uint64 time { owned get; }
      |                                   ^~~~~~~~~~  
../src/Services/Transfer.vala:26:35-26:44: error: `owned' accessor not allowed for specified property type
   26 |     public abstract uint64 size { owned get; }
      |                                   ^~~~~~~~~~  
../src/Services/Transfer.vala:27:42-27:51: error: `owned' accessor not allowed for specified property type
   27 |     public abstract uint64 transferred { owned get; }
      |                                          ^~~~~~~~~~  
../src/Services/Session.vala:23:37-23:46: error: `owned' accessor not allowed for specified property type
   23 |     public abstract uchar channel { owned get; }
      |                                     ^~~~~~~~~~  
Compilation failed: 12 error(s), 2 warning(s)