ProtobufJsonPayloadConverter does not work correctly with shaded artifact

Expected Behavior

The ProtobufJsonPayloadConverter does not work correctly when using the shaded Temporal artifact, which is sometimes necessary to avoid gRPC version conflicts.

The problem is: https://github.com/temporalio/sdk-java/blob/81f3cc33be8c4d6dbda48321cbb0b7aee3915e31/temporal-sdk/src/main/java/io/temporal/common/converter/ProtobufJsonPayloadConverter.java#L51-L53

Here, MessageOrBuilder is rewritten in the byte-code to be io.temporal.shaded.com.google.protobuf.MessageOrBuilder, and so passing in a non-shaded value (as certainly client code will be using) fails, and the converter fails to convert the value.

The converter, whether it is shaded or not, should correctly recognize protobuf values coming from client code.

Actual Behavior

Protobuf values coming from client code are ignored, and serialization fails.

Steps to Reproduce the Problem

Using the shaded temporal artifact, run this code:

import com.google.protobuf.StringValue;
import io.temporal.common.converter.ProtobufJsonPayloadConverter;

class Test {
    public static void main(String[] args) {
        var converter = new ProtobufJsonPayloadConverter();
        var msg = StringValue.of("hello");
        var payloadOpt = converter.toData(msg);
        System.out.println(payloadOpt.isPresent());
    }
}

We can see that the payload is not present.

Specifications

• Version: 1.32.1
• Platform: N/A

Start with temporal-sdk/src/main/java/io/temporal/common/converter/ProtobufJsonPayloadConverter.java at the MessageOrBuilder check described in the issue. Run the shaded-artifact reproduction using StringValue.of("hello") and verify the converter's payload result. Done means protobuf values from client code are recognized and the reproduction reports a present payload in the shaded artifact.