Do not check pyls as a known server

Testing unmaintained version is not worth it as it does not run the
newest jedi/IPython stack and would make the CI too fragile

Author: krassowski

python_packages/jupyter_lsp/jupyter_lsp/tests/conftest.py

@@ -19,7 +19,6 @@
     "bash-language-server",
     "dockerfile-language-server-nodejs",
     "javascript-typescript-langserver",
-    "pyls",
     "python-lsp-server",
     "unified-language-server",
     "sql-language-server",