Incorrect encoding of nullable non-required field with default

[OlegYch]

using spec like this

{
  "openapi": "3.0.2",
  "components": {
    "schemas": {
      "test": {
        "type": "object",
        "properties": {
          "method": {
            "type": "string",
            "default": "",
            "example": "TEXT",
            "nullable": true
          }
        },
        "required": [
        ]
      }
    }
  }
}

and config like

addSbtPlugin("dev.guardrail" % "sbt-guardrail" % "1.0.0-M1")

libraryDependencies ++= Seq(
  "dev.guardrail" %% "guardrail-scala-pekko-http" % "1.0.0-M1",
)

Compile / guardrailTasks := List(
  ScalaClient(
    (Compile / resourceDirectory).value / "openapi" / "asd.json",
    pkg = "test",
    modules = List("pekko-http", "circe"),
  )
)

i get a compilation error

[error] 11 |case class Test(method: _root_.test.support.Presence[Option[String]] = _root_.test.support.Presence.Present(""))
[error]    |                                 Found:    ("" : String)
[error]    |                                 Required: Option[String]
[```