Remove StandaloneExtensionPybind11.cpp FT update as does not work with python 3.8 and old pybind11 (llvm#122697)

Description:
- Remove StandaloneExtensionPybind11.cpp FT update as does not work with
python 3.8 and old pybind11

This should also fix the failing toy.test:
llvm#122684 (comment)

cc @jpienaar

Author: vfdev-5

mlir/examples/standalone/python/StandaloneExtensionPybind11.cpp

@@ -12,11 +12,9 @@
 #include "Standalone-c/Dialects.h"
 #include "mlir/Bindings/Python/PybindAdaptors.h"
 
-namespace py = pybind11;
-
 using namespace mlir::python::adaptors;
 
-PYBIND11_MODULE(_standaloneDialectsPybind11, m, py::mod_gil_not_used()) {
+PYBIND11_MODULE(_standaloneDialectsPybind11, m) {
   //===--------------------------------------------------------------------===//
   // standalone dialect
   //===--------------------------------------------------------------------===//