JNI: Remove the synthetic "default constructor" marker added by the Kotlin compiler from the generated code and just pass null.

[vaind]

Followup from https://github.com/getsentry/sentry-dart/pull/2670/files#r1952391869

The generated code looks like this:

  /// from: `synthetic public void <init>(kotlin.jvm.internal.DefaultConstructorMarker defaultConstructorMarker)`
  /// The returned object must be released after use, by calling the [release] method.
  factory SentryFlutterPlugin$Companion(
    jni$_.JObject? defaultConstructorMarker,
  ) {
    final _$defaultConstructorMarker =
        defaultConstructorMarker?.reference ?? jni$_.jNullReference;
    return SentryFlutterPlugin$Companion.fromReference(_new$(
            _class.reference.pointer,
            _id_new$ as jni$_.JMethodIDPtr,
            _$defaultConstructorMarker.pointer)
        .reference);
  }

[sagar-h007]

Hi @liamappelbe , I’d like to work on this issue. My plan is to update jnigen so that synthetic Kotlin DefaultConstructorMarker parameters are not exposed in the generated Dart API and null is passed directly to the JNI constructor call instead. I’ll make sure this only applies to Kotlin-generated synthetic constructors and doesn’t affect regular Java constructors.

[liamappelbe]

Sounds good