Syntax checker fails for Hello World or otherwise minimal project

[villelikitalo]

Hi,

I spent some time fiddling around with erlang-ls plugin (0.48.0 with OTP 25) in VS Code and noticed that the syntax checking fails for a minimal project. That is, I had a Hello World -erlang implementation and very minimal erlang_ls.config. What seems to occur is that if nothing is defined for the lists enabled and disabled for diagnostics and code lenses in the config then function valid/1 ends up called with incorrect argument that is not a list (But rather null) in els_code_lens.erl:131 and els_diagnostics.erl:171.

Sorry, I am not going to install tools right now to try out building and testing
erlang-ls-valid-list.patch
a fix but a simple fix could be something alike the attached patch.