Fix: Resolve Issues in RestKafkaSender and SchemaRetriever

[this-Aditya]

This PR addresses two key issues:

1. TypeInfo Errors in RestKafkaSender:
The current approach using reflection and generics to set TypeInfo results in errors when using with radar-commons-android. This has been replaced with an implementation based on ParameterizedType, which is error-free.

2. SchemaRetriever Metadata Behavior:
The ContentConverters implementation utilizes SchemaRetriever::metadata, which sends a POST request to the /subject/topic_name endpoint, resulting in a 503 Service Unavailable error.
This behavior was not observed in previous versions, previously, a GET request was sent to the /subject/topic_name-key|value endpoint if that fails, then the POST is used.

These changes have been tested and work seamlessly with RADAR-pRMT. Suggestions for alternative solutions are welcome.

[yatharthranjan]

why not define the ktype as well?

[this-Aditya]

I attempted to define kotlinType using the following approaches:

typeOf<RecordData<K, V>>()
typeOf<RecordData<*, *>>()
typeOf<RecordData<Any, Any>>()

Here are the results:

KafkaSenderTrace: Failed to set reflection work: 
java.lang.IllegalArgumentException: Class declares 0 type parameters, but 2 were provided.
    at kotlin.reflect.full.KClassifiers.createType(KClassifiers.kt:53)

When trying:

try {
    val type = typeOf<RecordData<*, *>>()
    val reifiedType = type.javaType
    typeInfo = TypeInfo(RecordData::class, reifiedType, type)
    logger.trace("KafkaSenderTrace: Successfully set up the reflection work")
} catch (ex: Exception) {
    logger.warn("KafkaSenderTrace: Failed to set reflection work: ", ex)
}

I encountered similar errors with:

val type = typeOf<RecordData<Any, Any>>()
val reifiedType = type.javaType
typeInfo = TypeInfo(RecordData::class, reifiedType, type)

I am uncertain if this approach is optimal. I would appreciate any suggestions for improvements or more efficient alternatives.

[this-Aditya]

Also from the TypeInfo class, kotlinType is null by default, unlike other properties:

public data class TypeInfo(
    public val type: KClass<*>,
    public val reifiedType: Type,
    public val kotlinType: KType? = null
)

[yatharthranjan]

The POST issue is likely due to a bug here- https://github.com/RADAR-base/radar-commons/blame/4d2044f5a1ec7f7b6b8f4fa1d6433144e7501bac/radar-commons/src/main/java/org/radarbase/producer/schema/SchemaRestClient.kt#L122, this should be calling schemaGet, not schemaPost.

[this-Aditya]

If we update it to a GET request, we should fetch the schemas by version or ID. We don't have either of these at the moment. Should I proceed with "latest", which will fetch the latest version?