element-hq/element-ios/issues/5120 - Keep old behavior for keys not c…

…reated through json decoding.

MatrixSDK/Crypto/Data/MXKey.m

@@ -101,17 +101,26 @@ + (id)modelFromJSON:(NSDictionary *)JSONDictionary
 - (NSDictionary *)JSONDictionary
 {
     NSDictionary *JSONDictionary;
-
+    
     NSString *keyFullId = self.keyFullId;
-    if (keyFullId && _value)
+    if (keyFullId && self.value)
     {
         JSONDictionary = @{
-                           keyFullId: _value
-                           };
+            keyFullId: self.value
+        };
     }
     return JSONDictionary;
 }
 
+- (NSDictionary *)signalableJSONDictionary
+{
+    if (_signalableJSONDictionary == nil) {
+        return @{ @"key": self.value };
+    }
+
+    return _signalableJSONDictionary;
+}
+
 - (NSString *)description
 {
     return self.JSONDictionary.description;