[lldb/Interpreter] Make `ScriptedInterface::ErrorWithMessage` static (NFC)

This patch changes the `ScriptedInterface::ErrorWithMessage` method to
make it `static` which makes it easier to call.

The patch also updates its various call sites to reflect this change.

Differential Revision: https://reviews.llvm.org/D117374



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