message: Fix tier2 SDK generation
diff: @@ -5,7 +5,7 @@ use smithy.test#httpResponseTests
  apply ValidationException @httpResponseTests([
  {
  - id: "lowercase message",
  + id: "LowercaseMessage",
  documentation: "This test case validates case insensitive parsing of `message`",
  params: {
  Message: "1 validation error detected"
  @@ -28,7 +28,7 @@ apply ValidationException @httpResponseTests([
  },
  {
  - id: "uppercase message",
  + id: "UppercaseMessage",
  documentation: "This test case validates case insensitive parsing of `message`",
  params: {
  Message: "Invalid volume size: 99999999999",
  