[lldb/Interpreter] Conform ScriptedProcessPythonInterface to SWIG python types

This patch should address the compiler warnings due to mismatch type
comparaison.

Differential Revision: https://reviews.llvm.org/D105788

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

lldb/source/Plugins/ScriptInterpreter/Python/ScriptedProcessPythonInterface.h

@@ -51,7 +51,7 @@ public:
   bool IsAlive() override;
 
 protected:
-  size_t GetGenericInteger(llvm::StringRef method_name);
+  llvm::Optional<uint64_t> GetGenericInteger(llvm::StringRef method_name);
   Status GetStatusFromMethod(llvm::StringRef method_name);
 
 private: