Serialization Bug: Including Null Properties in JSON Output instead of Excluding Them

[aniltonjunior]

Describe the bug:
The serialization of models using the toArray and toJSON functions is including null properties instead of excluding them from the JSON string. These additional fields will cause an error when trying to instantiate the model with the saved JSON string.

Expected behavior:
I understand that using the object's properties is not the best approach. It is necessary to use only the information contained in the RawModelDataInput field, where the object's state is stored.

Schema:

"juros": {
	"$id": "#juros",
	"type": "object",
	"required": [
		"id"
	],
	"properties": {
		"id": {
			"type": ["integer", "string"],
			"description": "ID ou Sigla do tipo de indicador utilizado."
		},
		"dataInicioJuros": {
			"type": "string",
			"format": "datetime"
			"description": "Data de início de fluência dos juros."
		},
		"dataFinalJuros": {
			"type": "string",
			"format": "datetime"
			"description": "Data de término de fluência dos juros."
		},
		"jurosProRata": {
			"type": "boolean",
			"description": "Indica que o cálculo de juros considerará frações de períodos"
		},
		"jurosCompostos": {
			"type": "boolean",
			"description": "Indica que o cálculo de juros será da modalidade de juros compostos"
		}
	}
},

Version:
0.23.0

Additional context:
Considering the schema, I would like to create a model with the JSON string {"id": "JUROS_0"} and serialize it to the same output. However, the class will generate the following output JSON string: {"id": "JUROS_0", "dataInicioJuros": null, "dataFimJuros": null, "jurosProRata": null, "jurosCompostos": null}.

[wol-soft]

Thanks for the report! Now properties which are optional and weren't provided in the initial data will be skipped in the serialization to generate a compatible serialized representation.
The properties will be included if they provide a default value or if the implicitNull option is enabled (compare e560d20#diff-cf7ae3135655cadc9420935644f596f479b07240ac019d479b872fc886b1eeb1)