Tdrd 607 fix terraform warnings inline policy (#560)

* removing inline policy

* attach policy not inline

root_draft_metadata.tf

@@ -48,11 +48,22 @@ module "draft_metadata_api_gateway" {
 resource "aws_iam_role" "draft_metadata_api_gateway_execution_role" {
   name               = "TDRMetadataChecksAPIGatewayExecutionRole${title(local.environment)}"
   assume_role_policy = templatefile("./templates/iam_policy/assume_role_policy.json.tpl", { service = "apigateway.amazonaws.com" })
+}
 
-  inline_policy {
-    name   = "TDRMetadataChecksAPIGatewayStepFunctionExecutionPolicy${title(local.environment)}"
-    policy = templatefile("./templates/iam_policy/api_gateway_state_machine_policy.json.tpl", { account_id = data.aws_caller_identity.current.account_id, state_machine_arn = module.draft_metadata_checks.step_function_arn })
-  }
+resource "aws_iam_policy" "api_gateway_execution_policy" {
+  name = "TDRMetadataChecksAPIGatewayStepFunctionExecutionPolicy${title(local.environment)}"
+  policy = templatefile(
+    "./templates/iam_policy/api_gateway_state_machine_policy.json.tpl",
+    {
+      account_id        = data.aws_caller_identity.current.account_id,
+      state_machine_arn = module.draft_metadata_checks.step_function_arn
+    }
+  )
+}
+
+resource "aws_iam_role_policy_attachment" "api_gateway_execution_policy" {
+  role       = aws_iam_role.draft_metadata_api_gateway_execution_role.name
+  policy_arn = aws_iam_policy.api_gateway_execution_policy.arn
 }
 
 module "draft_metadata_bucket" {