chore: add smoke test traits dep

Adds a dependency on smithy-smoke-test-traits in the sdk code gen
package so aws service models that use the smokeTests trait won't
fail to build because of unknown traits. Generated a client with
a smoke test and confirmed there was no diff.

Adding the dependency in the code gen package since it's the models
that need the dependency, not the code generator. When smoke tests
are implemented in the generator, we can add the dep there.

codegen/sdk-codegen/build.gradle.kts

@@ -43,7 +43,9 @@ plugins {
 }
 
 dependencies {
+    val smithyVersion: String by project
     implementation(project(":smithy-aws-typescript-codegen"))
+    implementation("software.amazon.smithy:smithy-smoke-test-traits:$smithyVersion")
 }
 
 // This project doesn't produce a JAR.