Revert "[lldb] Check for abstract methods implementation in Scripted Plugin Objects (#71260)"

This reverts commit cc9ad72713 since it
breaks some tests upstream:

https://lab.llvm.org/buildbot/#/builders/68/builds/63112

********************
Failed Tests (4):
  lldb-api :: functionalities/gdb_remote_client/TestThreadSelectionBug.py
  lldb-api :: functionalities/plugins/python_os_plugin/TestPythonOSPlugin.py
  lldb-api :: functionalities/plugins/python_os_plugin/stepping_plugin_threads/TestOSPluginStepping.py
  lldb-api :: functionalities/postmortem/mach-core/TestMachCore.py

lldb/source/Plugins/ScriptInterpreter/Python/PythonDataObjects.cpp

@@ -663,20 +663,6 @@ bool PythonDictionary::Check(PyObject *py_obj) {
   return PyDict_Check(py_obj);
 }
 
-bool PythonDictionary::HasKey(const llvm::Twine &key) const {
-  if (!IsValid())
-    return false;
-
-  PythonString key_object(key.isSingleStringRef() ? key.getSingleStringRef()
-                                                  : key.str());
-
-  if (int res = PyDict_Contains(m_py_obj, key_object.get()) > 0)
-    return res;
-
-  PyErr_Print();
-  return false;
-}
-
 uint32_t PythonDictionary::GetSize() const {
   if (IsValid())
     return PyDict_Size(m_py_obj);