[lldb] Fix assertions caused by un-checked errors in ScriptedProcess

This patch should fix some assertion that started getting hit after f22d82c.

That commit changed the scripted object plugin creation to use
`llvm::Expected<T>` as a return type to enforce error handling, however
I forgot to handle the error which caused the assert.

The interesting  part about this, is that since that assert was triggered
in the ScriptedProcess constructor (where the `llvm::Error` wasn't
handled), that impacted every test that launched any kind of process,
since the process plugin manager would eventually also iterate over the
`ScriptedProcess::Create` factory method.

This patch should fix the assertions by handling the errors.

Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>

lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp

@@ -113,6 +113,7 @@ ScriptedProcess::ScriptedProcess(lldb::TargetSP target_sp,
       m_scripted_metadata.GetArgsSP());
 
   if (!obj_or_err) {
+    llvm::consumeError(obj_or_err.takeError());
     error.SetErrorString("Failed to create script object.");
     return;
   }