fix json decode quirk for xiaomi e10 (#1922)

Version:
Firmware version: `2.2.4_0050`
Hardware version: `esp32`

some commands (e.g. `genericmiot call map:rename-map '[0,"string"]'`)
generate json-like string like this:
```json
{"id":2,"result":,"exe_time":0}
```
and this produce the error:
```log
ERROR:miio.protocol:Unable to parse json 'b'{"id":2,"result":,"exe_time":0}'': Expecting value: line 1 column 18 (char 17)
ERROR:miio.click_common:Exception: Unable to parse message payload
```
I fix that by removing the nonsense `result":,`.

---------

Co-authored-by: Teemu Rytilahti <[email protected]>

miio/protocol.py

@@ -194,6 +194,8 @@ def _decode(self, obj, context, path) -> Union[Dict, bytes]:
             ),
             # fix double commas for xiaomi.vacuum.b112, fw: 2.2.4_0049
             lambda decrypted_bytes: decrypted_bytes.replace(b",,", b","),
+            # fix "result":," no sense key for xiaomi.vacuum.b112, fw:2.2.4_0050
+            lambda decrypted_bytes: decrypted_bytes.replace(b'"result":,', b""),
         ]
 
         for i, quirk in enumerate(decrypted_quirks):

miio/tests/test_protocol.py

@@ -151,6 +151,17 @@ def test_decode_json_quirk_cloud(token):
     assert parsed_msg.data.value["id"] == 123456
 
 
+def test_decode_json_empty_result(token):
+    """Test for quirk handling on empty result seen with xiaomi.vacuum.b112."""
+    ctx = {"token": token}
+    serialized_msg = build_msg(b'{"id":2,"result":,"exe_time":0}', token)
+    parsed_msg = Message.parse(serialized_msg, **ctx)
+
+    assert parsed_msg.data.value
+    assert isinstance(parsed_msg.data.value, dict)
+    assert parsed_msg.data.value["id"] == 2
+
+
 def test_decode_json_raises_for_invalid_json(token):
     ctx = {"token": token}