vortex: Basic Variant IO support

[AdamGS]

Adds basic support for variant in Vortex through the generic record-based writer.

Depends on:

• Support for importing Arrow extension arrays into core vortex arrays and ParquetVariant support. vortex-data/vortex#8125
• Support ParquetVariant through JNI vortex-data/vortex#8129

Work that is still missing here:

• min/max bounds for variant array

[robert3005]

you also have this failure

TestGenericVortex > testTypeSchema(Type) > [19] variant FAILED
    org.apache.iceberg.exceptions.RuntimeIOException: Failed to write Vortex batch
        at app//org.apache.iceberg.vortex.VortexFileAppender.flushBatch(VortexFileAppender.java:103)
        at app//org.apache.iceberg.vortex.VortexFileAppender.close(VortexFileAppender.java:129)
        at app//org.apache.iceberg.vortex.TestGenericVortex.writeAndValidate(TestGenericVortex.java:91)
        at app//org.apache.iceberg.vortex.TestGenericVortex.writeAndValidate(TestGenericVortex.java:72)
        at app//org.apache.iceberg.vortex.TestGenericVortex.writeAndValidate(TestGenericVortex.java:61)

        Caused by:
        java.io.IOException: failed to write batch
            at dev.vortex.api.VortexWriter.writeBatch(VortexWriter.java:75)
            at org.apache.iceberg.vortex.VortexFileAppender.flushBatch(VortexFileAppender.java:101)
            ... 4 more

            Caused by:
            java.lang.RuntimeException: Vortex Error: Other error: write schema mismatch: expected {id=i64, test_type=variant?, trailing_data=utf8}, got {id=i64, test_type={metadata=binary, value=binary?}?, trailing_data=utf8}
                at dev.vortex.jni.NativeWriter.writeBatch(Native Method)
                at dev.vortex.api.VortexWriter.writeBatch(VortexWriter.java:73)
                ... 5 more

[AdamGS]

I think the failure is fixed in upstream Voretx.

[AdamGS]

ok now there's some spark stuff I need to fix, will get to it later this week.