[Bug] KwRestArg value is sometimes not ujson.Str

[DavidBakerEffendi]

Describe the bug
On mastodon, we see the value field not being a string, and this is not being handled gracefully.

// RubyJsonToNodeCreator
  private def visitKwRestArg(obj: Obj): RubyExpression = {
    val name = obj(ParserKeys.Value).str // <-- here
    HashParameter(name)(obj.toTextSpan)
  }

To Reproduce
Steps to reproduce the behavior:

1. git clone [email protected]:mastodon/mastodon.git --depth 1
2. joern-parse mastodon
3. See error