[lldb] Fix another GCC build failure in ScriptedPythonInterface.h

In 6c961ae1, I've introduced a new explicit fully specialized templated method
`ScriptedPythonInterface::ReverseTransform(bool&, PythonObject, Status&)`.

However, that explicit specialization is causing GCC to choke when
building the file as shown here:

https://lab.llvm.org/buildbot/#/builders/217/builds/20430

To address that issue, this patch turns the method explicit specialization
into an method overload.

Differential Revision: https://reviews.llvm.org/D149218



Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>