[mlir][python] disable nanobind leak warnings (#121099)

Author: makslevental

IRCore.cpp

@@ -2587,6 +2587,8 @@ class PyOpAttributeMap {
 //------------------------------------------------------------------------------
 
 void mlir::python::populateIRCore(nb::module_ &m) {
+  // disable leak warnings which tend to be false positives.
+  nb::set_leak_warnings(false);
   //----------------------------------------------------------------------------
   // Enums.
   //----------------------------------------------------------------------------