[lldb] NFC: Use standard comment for lldb-python.h include (#181498)
## Summary
Use the standard `// LLDB Python header must be included first.` comment
to match every other Python interface `.cpp` file in this directory, as
suggested by @JDevlieghere.
## Test plan
NFC - comment only change.
Co-authored-by: Rahul Reddy Chamala <rachamal@meta.com>