IDE shows error when a venv starter is removed

[t-kalinowski]

The IDE shows a cryptic error message when probing a broken venv as part of its start up routine:

Restarting R session...

Error in system2(command = python, args = shQuote(script), stdout = TRUE,  : 
  error in running command
Calls: do.call ... <Anonymous> -> python_config -> python_config_impl -> system2
Execution halted
> 

(It's not actually an error, just a warning)

This is a different manifestation of #1441.

reprex:

1. reticulate:::rm_all_reticulate_state()
2. install_python()
3. virtualenv_create() # r-reticulate
4. unlink("~/.pyenv", recursive = TRUE)
5. restart R session in the IDE (cmd+shift+0)

[t-kalinowski]

The error message is improved, but the real fix is better done in the IDE.

New warning shown:

Restarting R session...

Error in python_config_impl(python) : 
  Error running '/Users/tomasz/.virtualenvs/r-reticulate/bin/python': No such file.
The Python installation used to create the virtualenv has been moved or removed:
  '/Users/tomasz/.pyenv/versions/3.9.17/bin'
Calls: do.call ... <Anonymous> -> <Anonymous> -> python_config -> python_config_impl
Execution halted
>

The line in the IDE that causes the error to be shown: https://github.com/rstudio/rstudio/blob/ffd3ddbe7b45741a16ccf54d5a72a51c86a99bb6/src/cpp/session/modules/SessionReticulate.R#L2124C1-L2124C69

That surrounding tryCatch() should probably capture and silence errors, (and warning too). If py_discover_config() raises an error, that error shouldn't be shown until the user attempts to initialize Python in the R session.