fix(jsonschema): make all required properties optional in PATCH operation with 'json' format

[ttskch]

[!NOTE] Is this a new feature? If so, we can close this PR and go to #6395.

Q	A
Branch?	3.3
Tickets	N/A
License	MIT
Doc PR	N/A

In the schema for the request body of application/merge-patch+json PATCH operation, all required properties should be output as optional.

See here: https://datatracker.ietf.org/doc/html/rfc7386#section-3

This PR fixes the SchemaFactory for the 'json' format to output required properties as optional only for input context of PATCH operations.

For example, for the following entity, the output of the OpenAPI document will change as follows:

#[ORM\Entity(repositoryClass: TodoRepository::class)]
#[ApiResource]
class Todo
{
    #[ORM\Id]
    #[ORM\GeneratedValue]
    #[ORM\Column]
    private ?int $id = null;

    #[ORM\Column(length: 255)]
    #[Assert\NotBlank]
    #[Assert\Length(max: 255)]
    private ?string $title = null;

    #[ORM\Column(type: Types::TEXT, nullable: true)]
    private ?string $description = null;

    #[ORM\Column]
    #[Assert\NotNull]
    private ?bool $done = null;

	Before	After
PATCH Operation
Schemas

[soyuka]

I think that we can make this a bug fix as it won't break any current implementations