Can't open Codi if [Nerd,Neo]Tree is open

[jeff-dh]

Issue description

• Brief description
  If I a have a filetree open (tested with NERDTree and Neotree) I can't start Codi and get an error messages.
• Expected results
  Codi! (and no error messages ;)
• Actual results
  I get the following error message:

Error detected while processing function codi#run[36]..<SNR>90_codi_spawn[95]..codi#update[5]..<SNR>90_codi_do_update:
line    7:
E715: Dictionary required
line   10:
E715: Dictionary required
Error detected while processing function <SNR>90_codi_nvim_callback[18]..function <SNR>90_codi_nvim_callback[15]..<SNR>90_codi_handle_data[6]..<SNR>90_preprocess:
line    6:
E715: Dictionary required
E21: Cannot make changes, 'modifiable' is off

• A minimal .vimrc that will reproduce the issue
  too much work right now, sorry. If you can't reproduce it I will create one...
• Exact steps to reproduce the issue, starting with the command used to open
  vim

nvim
:NERDTree -- or Neotree
<C-w>l -- activate empty buffer again
:Codi python

Environment

• Operating system
  Mint 21
• Version of script
  6537ba6
• The following in a pastebin, to reduce visual clutter:
  • Entire output of vim --version & Log lines (see :h g:codi#log)
    https://gist.github.com/jeff-dh/00a28de212179affc5352fc181892c96