Fix serialization of blob shapes

Author: lauzadis

codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/rendering/serde/SerializeStructGenerator.kt

@@ -647,7 +647,6 @@ open class SerializeStructGenerator(
         val target = member.targetOrSelf(ctx.model)
 
         val encoded = when {
-            target.type == ShapeType.BLOB -> writer.format("#L.#T()", identifier, RuntimeTypes.Core.Text.Encoding.encodeBase64String)
             target.type == ShapeType.TIMESTAMP -> {
                 writer.addImport(RuntimeTypes.Core.TimestampFormat)
                 val tsFormat = member

codegen/smithy-kotlin-codegen/src/test/kotlin/software/amazon/smithy/kotlin/codegen/rendering/serde/SerializeStructGeneratorTest.kt

@@ -1822,7 +1822,7 @@ class SerializeStructGeneratorTest {
 
         val expected = """
             serializer.serializeStruct(OBJ_DESCRIPTOR) {
-                input.fooBlob?.let { field(FOOBLOB_DESCRIPTOR, it.encodeBase64String()) }
+                input.fooBlob?.let { field(FOOBLOB_DESCRIPTOR, it) }
             }
         """.trimIndent()
 

runtime/serde/serde-xml/common/src/aws/smithy/kotlin/runtime/serde/xml/XmlSerializer.kt

@@ -134,7 +134,7 @@ public class XmlSerializer(private val xmlWriter: XmlStreamWriter = xmlStreamWri
         field(descriptor, value.format(format))
 
     override fun field(descriptor: SdkFieldDescriptor, value: ByteArray): Unit =
-        field(descriptor, value)
+        field(descriptor, value.encodeBase64String())
 
     override fun field(descriptor: SdkFieldDescriptor, value: Document?): Unit = throw SerializationException(
         "cannot serialize field ${descriptor.serialName}; Document type is not supported by xml encoding",