Add support to Sequence[int] similar to Sequence[str] for addon commands

[m417z]

Problem Description

Addon commands can be sequences, but the only supported sequence is of type str. Add support for Sequence[int]. https://github.com/mitmproxy/mitmproxy/blob/1f2e1a254a68e54e60360b66762ed6bdf2ff26be/docs/src/content/addons-commands.md?plain=1#L120 https://github.com/mitmproxy/mitmproxy/blob/1f2e1a254a68e54e60360b66762ed6bdf2ff26be/mitmproxy/optmanager.py#L368

Additional context

Example use case: passing multiple status codes. https://github.com/realgam3/pymultitor/pull/38

[mhils]

Happy to merge a PR for this! 😃