Slow completion for python-igraph depending on current working directory

### Issue

Completions for [python-igraph](https://github.com/igraph/python-igraph) are typically very slow, but the speed depends drastically on the current working directory.

If vim is run in `~`, the code
```
from igraph import Graph
g = Graph()
g.
```
takes over 30 seconds to complete. The completion becomes faster if the current working directory is better isolated from other directories. (The examples below will hopefully help to clarify what I mean by this; unfortunately I don't know how to give a precise characterization of "isolated".)

### Steps to reproduce

After cd'ing into the following directories:

1. `~`
2. `~/Python/empty` (an empty directory, but `~/Python` contains all my Python projects and scripts)
3. `~/empty/directory/with/no/python/anywhere/in/sight`

I start vim and type the code
```
from igraph import Graph
g = Graph()
g.
```
In case 1, the completion takes over 30 seconds, in case 2 it takes about 3 seconds, and in case 3 it happens basically instantaneously.

Tab completion in ipython is instantaneous in all three cases.

Vim is run with a minimal .vimrc that uses [vim-plug](https://github.com/junegunn/vim-plug) to load only jedi-vim:
```
set nocompatible

call plug#begin()
Plug 'davidhalter/jedi-vim'
call plug#end()
```

### Output of “:verbose JediDebugInfo”

#### Jedi-vim debug information

##### jedi-vim version

- jedi-vim git version: b82da7d
- jedi git submodule status: 4e175ca82bbd680cb90f462545c10a8b1c0b5f2e pythonx/jedi (v0.19.1)
- parso git submodule status: ee5edaf22ff3941cbdfa4efd8cb3e8f69779fd56 pythonx/parso (v0.8.3)

##### Global Python

Using Python version 3 to access Jedi.
- global sys.executable: `/home/ilkka/mambaforge/envs/3.11/bin/python3`
- global sys.version: `3.10.12 (main, Nov 20 2023, 15:14:05) [GCC 11.4.0]`
- global site module: `/home/ilkka/mambaforge/lib/python3.10/site.py`

##### Jedi

- path: `/home/ilkka/.vim/plugged/jedi-vim/pythonx/jedi/jedi/__init__.py`
- version: 0.19.1

##### Jedi environment:

- executable: /home/ilkka/mambaforge/envs/3.11/bin/python
- sys_path:
- `/home/ilkka/mambaforge/envs/3.11/lib/python311.zip`
- `/home/ilkka/mambaforge/envs/3.11/lib/python3.11`
- `/home/ilkka/mambaforge/envs/3.11/lib/python3.11/lib-dynload`
- `/home/ilkka/mambaforge/envs/3.11/lib/python3.11/site-packages`

##### Known environments

- (/home/ilkka/mambaforge/envs/3.11/bin/python)

- (/home/ilkka/mambaforge/envs/3.11/bin/python3.11)

- (/usr/bin/python3.10)

##### Settings

```
omnifunc=jedi#completions
Last set from ~/.vim/plugged/jedi-vim/autoload/jedi.vim line 723
completeopt=menuone,longest,popup
Last set from ~/.vim/plugged/jedi-vim/autoload/jedi.vim line 701
```

#### :version
```

VIM - Vi IMproved 8.2 (2019 Dec 12, compiled Dec 05 2023 17:58:57)
Included patches: 1-579, 1969, 580-1848, 4975, 5016, 5023, 5072, 2068, 1849-1854, 1857, 1855-1857, 1331, 1858, 1858-1859, 1873, 1860-1969, 1992, 1970-1992, 2010, 1993-2068, 2106, 2069-2106, 2108, 2107-2109, 2109-3995, 4563, 4646, 4774, 4895, 4899, 4901, 4919, 213, 1840, 1846-1847, 2110-2112, 2121
Modified by team+vim@tracker.debian.org
Compiled by team+vim@tracker.debian.org
Huge version with GTK3 GUI. Features included (+) or not (-):
+acl +dnd +listcmds +postscript +termresponse
+arabic -ebcdic +localmap +printer +textobjects
+autocmd +emacs_tags +lua +profile +textprop
+autochdir +eval +menu -python +timers
-autoservername +ex_extra +mksession +python3 +title
+balloon_eval +extra_search +modify_fname +quickfix +toolbar
+balloon_eval_term -farsi +mouse +reltime +user_commands
+browse +file_in_path +mouseshape +rightleft +vartabs
++builtin_terms +find_in_path +mouse_dec +ruby +vertsplit
+byte_offset +float +mouse_gpm +scrollbind +vim9script
+channel +folding -mouse_jsbterm +signs +viminfo
+cindent -footer +mouse_netterm +smartindent +virtualedit
+clientserver +fork() +mouse_sgr +sodium +visual
+clipboard +gettext -mouse_sysmouse +sound +visualextra
+cmdline_compl -hangul_input +mouse_urxvt +spell +vreplace
+cmdline_hist +iconv +mouse_xterm +startuptime +wildignore
+cmdline_info +insert_expand +multi_byte +statusline +wildmenu
+comments +ipv6 +multi_lang -sun_workshop +windows
+conceal +job -mzscheme +syntax +writebackup
+cryptv +jumplist +netbeans_intg +tag_binary +X11
+cscope +keymap +num64 -tag_old_static -xfontset
+cursorbind +lambda +packages -tag_any_white +xim
+cursorshape +langmap +path_extra +tcl +xpm
+dialog_con_gui +libcall +perl +termguicolors +xsmp_interact
+diff +linebreak +persistent_undo +terminal +xterm_clipboard
+digraphs +lispindent +popupwin +terminfo -xterm_save
system vimrc file: "$VIM/vimrc"
user vimrc file: "$HOME/.vimrc"
2nd user vimrc file: "~/.vim/vimrc"
user exrc file: "$HOME/.exrc"
system gvimrc file: "$VIM/gvimrc"
user gvimrc file: "$HOME/.gvimrc"
2nd user gvimrc file: "~/.vim/gvimrc"
defaults file: "$VIMRUNTIME/defaults.vim"
system menu file: "$VIMRUNTIME/menu.vim"
fall-back for $VIM: "/usr/share/vim"
Compilation: gcc -c -I. -Iproto -DHAVE_CONFIG_H -DFEAT_GUI_GTK -pthread -I/usr/include/gtk-3.0 -I/usr/include/at-spi2-atk/2.0 -I/usr/include/at-spi-2.0 -I/usr/include/dbus-1.0 -I/usr/lib/x86_64-linux-gnu/dbus-1.0/include -I/usr/include/gtk-3.0 -I/usr/include/gio-unix-2.0 -I/usr/include/cairo -I/usr/include/pango-1.0 -I/usr/include/harfbuzz -I/usr/include/pango-1.0 -I/usr/include/fribidi -I/usr/include/harfbuzz -I/usr/include/atk-1.0 -I/usr/include/cairo -I/usr/include/pixman-1 -I/usr/include/uuid -I/usr/include/freetype2 -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/libpng16 -I/usr/include/x86_64-linux-gnu -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -Wdate-time -g -O2 -ffile-prefix-map=/build/vim-gVT2fw/vim-8.2.3995=. -flto=auto -ffat-lto-objects -flto=auto -ffat-lto-objects -fstack-protector-strong -Wformat -Werror=format-security -D_REENTRANT -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
Linking: gcc -L. -Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,-z,now -fstack-protector-strong -rdynamic -Wl,-export-dynamic -Wl,-E -Wl,-Bsymbolic-functions -flto=auto -ffat-lto-objects -flto=auto -Wl,-z,relro -Wl,-z,now -Wl,--as-needed -o vim -lgtk-3 -lgdk-3 -lpangocairo-1.0 -lpango-1.0 -lharfbuzz -latk-1.0 -lcairo-gobject -lcairo -lgdk_pixbuf-2.0 -lgio-2.0 -lgobject-2.0 -lglib-2.0 -lSM -lICE -lXpm -lXt -lX11 -lXdmcp -lSM -lICE -lm -ltinfo -lselinux -lcanberra -lsodium -lacl -lattr -lgpm -L/usr/lib -llua5.2 -Wl,-E -fstack-protector-strong -L/usr/local/lib -L/usr/lib/x86_64-linux-gnu/perl/5.34/CORE -lperl -ldl -lm -lpthread -lcrypt -L/usr/lib/python3.10/config-3.10-x86_64-linux-gnu -lpython3.10 -lcrypt -ldl -lm -lm -L/usr/lib/x86_64-linux-gnu -ltcl8.6 -ldl -lz -lpthread -lm -lruby-3.0 -lm -L/usr/lib
```

#### :messages
```
Messages maintainer: Bram Moolenaar

```

:scriptnames

```
1: ~/jedi.vimrc
2: ~/.vim/autoload/plug.vim
3: /usr/share/vim/vim82/filetype.vim
4: /usr/share/vim/vim82/ftplugin.vim
5: /usr/share/vim/vim82/indent.vim
6: /usr/share/vim/vim82/syntax/syntax.vim
7: /usr/share/vim/vim82/syntax/synload.vim
8: /usr/share/vim/vim82/syntax/syncolor.vim
9: /usr/share/vim/vim82/colors/lists/default.vim
10: ~/.vim/plugged/jedi-vim/plugin/jedi.vim
11: /usr/share/vim/vim82/plugin/getscriptPlugin.vim
12: /usr/share/vim/vim82/plugin/gzip.vim
13: /usr/share/vim/vim82/plugin/logiPat.vim
14: /usr/share/vim/vim82/plugin/manpager.vim
15: /usr/share/vim/vim82/plugin/matchparen.vim
16: /usr/share/vim/vim82/plugin/netrwPlugin.vim
17: /usr/share/vim/vim82/plugin/rrhelper.vim
18: /usr/share/vim/vim82/plugin/spellfile.vim
19: /usr/share/vim/vim82/plugin/tarPlugin.vim
20: /usr/share/vim/vim82/plugin/tohtml.vim
21: /usr/share/vim/vim82/plugin/vimballPlugin.vim
22: /usr/share/vim/vim82/plugin/zipPlugin.vim
23: ~/.vim/plugged/jedi-vim/ftplugin/python/jedi.vim
24: ~/.vim/plugged/jedi-vim/autoload/jedi.vim
25: /usr/share/vim/vim82/ftplugin/python.vim
26: ~/.vim/plugged/jedi-vim/after/ftplugin/python/jedi.vim
27: /usr/share/vim/vim82/indent/python.vim
28: ~/.vim/syntax/python.vim
29: /usr/share/vim/vim82/syntax/python.vim
30: ~/.vim/plugged/jedi-vim/after/syntax/python.vim
```

Reproduce the python-igraph completion in the three working-directory cases, using the `omnifunc=jedi#completions` entry point. Then read `autoload/jedi.vim`, `ftplugin/python/jedi.vim`, and the reported Jedi environment details to trace the directory-dependent delay. Done means completion is responsive and no longer varies drastically with the current working directory.

Written by the indexing model from the issue text.