[mlir][ods] Handle DeclareOpInterfaceMethods in formatgen

Previously it would not consider ops with
DeclareOpInterfaceMethods<InferTypeOpInterface> as having the
InferTypeOpInterface interfaces added. The OpInterface nested inside
DeclareOpInterfaceMethods is not retained so that one could query it, so
check for the the C++ class directly (a bit raw/low level - will be
addressed in follow up).

Differential Revision: https://reviews.llvm.org/D116572