[lldb][NFC] Remove unnecessary includes in source/Commands

Summary: This removes most of unnecessary includes in the `source/Commands` directory. This was generated by IWYU and a script that fixed all the bogus reports from IWYU. Patch is tested on Linux and macOS.

Reviewers: JDevlieghere

Reviewed By: JDevlieghere

Subscribers: krytarowski, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D71489