Ability to manually reset `pending_request` flag

Is your feature request related to a problem? Please describe.

Unfortunately, I've sometimes gotten lsp-saga stuck on a code action such that I requested it and then some error caused it to abort. I am however not able to reproduce this reliably (so far, it only happened in a buffer which suspiciously had a broken treesitter parser). This gets lsp-saga into a state where it can no longer process further code action requests. It would be nice to have an escape hatch for this.

Describe the solution you'd like

A command such as :Lspsaga reset_state could be introduced that reset the pending_request variable in codeaction and other places where such a variable is used.

Describe alternatives you've considered

Restarting Neovim is the only solution I'm aware of at the moment. Obviously, the best solution would be to address the root cause, but as I've mentioned I haven't been able to reliably invoke this behavior. I'll open another issue in case I find out more here. Additionally, this system is inherently a little prone to this breakage, so being able to do a clean reset is probably handy anyways.

Start by locating the codeaction request handling and every place where a pending_request state is used; the issue names no files or tests. Check how existing Lspsaga commands are registered, then define what a reset_state command must clear and verify that subsequent code action requests work again.