Fix TelemetryConverter to preserve schema URL from spans

The test framework was not copying the schema URL from the protobuf
ScopeSpans to the InstrumentationScopeInfo when converting spans,
causing all schema URL assertions to fail even though spans were
correctly emitting schema URLs.

Author: trask

testing-common/src/main/java/io/opentelemetry/instrumentation/testing/internal/TelemetryConverter.java

@@ -126,6 +126,7 @@ public static List<SpanData> getSpanData(Collection<ResourceSpans> allResourceSp
                           // emptyToNull since they are the same at protobuf layer,
                           // and allows for simpler verification of InstrumentationScope
                           .setVersion(emptyToNull(instrumentationScope.getVersion()))
+                          .setSchemaUrl(emptyToNull(ilSpans.getSchemaUrl()))
                           .build())
                   .setName(span.getName())
                   .setStartEpochNanos(span.getStartTimeUnixNano())