Delete tintype_debug_launcher

Summary:
Deletes the legacy pydevd-based `tintype_debug_launcher` now that all consumers use the native `tintype_dap_server`. The agentic postmortem path and the VS Code postmortem deeplink no longer reference it, and `_reconstruct_exception` now lives in `sand/agents/python_postmortem/snapshot.py`.

Removes the `python_binary` (`//tintype/fb:tintype_debug_launcher`), the core `python_library` (`//tintype/utils:tintype_debug_launcher`), the `cli.deployer`, the checked-in dotslash stub, the unit test, and the MSDK allow-list entry.

Reviewed By: youngd007

Differential Revision: D114610950

fbshipit-source-id: e44d71d2aee5a79f0c062cf3d5fe8c7ea7a9c57b

Author: pdepetro