@property.array doesn't work if nulls are allowed

Describe the bug

Trying to make a model that maps to a nullable JSON or array column in PostgreSQL, so the entity property needs to permit nulls.

A property declared like this:

@property.array('string', {
	required: false,
})
foo!: string[] | null;

Produces a @property.array can only decorate array properties from here: https://github.com/loopbackio/loopback-next/blob/a60ae8e43a1ec9d65929f19bbd364e332f28503b/packages/repository/src/decorators/model.decorator.ts#L155

Trying to "hack" it like this:

@property({
	required: false,
	type: Array,
	itemType: 'string',
	jsonSchema: {
		type: 'array',
		nullable: true,
		items: { type: 'string' },
	},
})

Results in incorrect data being sent to PostgreSQL (get JSON syntax errors because it's sending the object as an array to the PG driver instead of the JSON.stringify it should be using, because the array check in loopback-connector-postgresql (https://github.com/loopbackio/loopback-connector-postgresql/blob/61b5029275487fc7812d774ab4be16dc8aacd726/lib/postgresql.js#L788) fails

Logs

No response

Additional information

No response

Reproduction

https://codesandbox.io/s/zen-thompson-keo2is

Lies packages/repository/src/decorators/model.decorator.ts bei der gemeldeten Prüfung der Array-Eigenschaft und vergleiche sie anschließend mit der Array-Verarbeitung in loopback-connector-postgresql/lib/postgresql.js. Reproduziere den Fall eines nullable Arrays mit der verlinkten CodeSandbox und überprüfe, dass der Decorator es akzeptiert und PostgreSQL gültiges JSON ohne Syntaxfehler erhält.