chore(awslint): fix nested submodule L1 type not recognized as L1 (#2…

…7273)

Previously a type from a submodule with a FQN like `aws_service.CfnTheResource.SubType` was not identified as an L1 type, and subjected to stricter L2 rules.

Fixes failing integration tests in https://github.com/cdklabs/awscdk-service-spec

E.g. https://github.com/cdklabs/awscdk-service-spec/actions/runs/6293221129/job/17097529390

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packages/awslint/lib/rules/core-types.ts

@@ -89,7 +89,10 @@ export class CoreTypes {
    * Return true if the given interface type is a CFN class or prop type
    */
   public static isCfnType(interfaceType: reflect.Type) {
-    return interfaceType.name.startsWith('Cfn') || (interfaceType.namespace && interfaceType.namespace.startsWith('Cfn'));
+    return interfaceType.name.startsWith('Cfn')
+      || (interfaceType.namespace && interfaceType.namespace.startsWith('Cfn'))
+      // aws_service.CfnTheResource.SubType
+      || (interfaceType.namespace && interfaceType.namespace.split('.', 2).at(1)?.startsWith('Cfn'));
   }
 
   /**