fix: only import transform namespace if there are modeled operations (#970)

Author: lauzadis

.changes/598b7088-0032-4336-8aab-3c242876301c.json

@@ -0,0 +1,5 @@
+{
+    "id": "598b7088-0032-4336-8aab-3c242876301c",
+    "type": "bugfix",
+    "description": "Fix codegen of services with no operations"
+}

codegen/smithy-kotlin-codegen/src/main/kotlin/software/amazon/smithy/kotlin/codegen/rendering/protocol/HttpProtocolClientGenerator.kt

@@ -128,7 +128,9 @@ abstract class HttpProtocolClientGenerator(
 
     protected open fun importSymbols(writer: KotlinWriter) {
         writer.addImport("${ctx.settings.pkg.name}.model", "*")
-        writer.addImport("${ctx.settings.pkg.name}.transform", "*")
+        if (TopDownIndex(ctx.model).getContainedOperations(ctx.service).isNotEmpty()) {
+            writer.addImport("${ctx.settings.pkg.name}.transform", "*")
+        }
 
         val defaultClientSymbols = setOf(
             RuntimeTypes.HttpClient.Operation.SdkHttpOperation,