Cannot install addons that aren't installed that are defined by a `${addon}` path in `.luarc.json`

Nobody has claimed this yet.

### Which OS are you using?

Windows

### Expected Behaviour

An "Install" button on the addon

### Actual Behaviour

A "Disable" button that when clicked errors

### Reproduction steps

1. Have no addons installed through the addon manager
2. Open a folder that already has a `.luarc.json` with `workspace.library` pointing to a path with `${addons}` placeholder (e.g. `"${addons}/garrysmod/module/library"`)
3. Try to install the addon through the addon manager to see that you only get a "Disable" button

### Additional Notes

The only workaround is to open another folder/workspace and then enable the addon manually.

It would also be nice to have a settings option you can throw into `.vscode/settings.json` to prompt the user to install addons required by the folder/workspace if they don't already have it installed.

### Log

Log

#### STARTUP ####

[2024-11-13 12:15:25] |   DEBUG   |       GENERAL      | Starting language server

[2024-11-13 12:15:25] |   DEBUG   |       GENERAL      | Language server has started

[2024-11-13 12:15:25] |   DEBUG   |       WebVue       | Workspace Open: true

[2024-11-13 12:15:25] |   DEBUG   |     Filesystem     | Created directory at "/C:/Users/c/AppData/Roaming/VSCodium/User/globalStorage/sumneko.lua/addonManager"

[2024-11-13 12:15:25] |  VERBOSE  |       Command      | Executing "getAddons" ({"command":"getAddons","data":{"page":1}})

[2024-11-13 12:15:26] |   ERROR   |    Addon Manager   | Failed to fetch addons! Please check your connection to GitHub.

[2024-11-13 12:15:26] |   ERROR   |    Addon Manager   | Cannot rebase onto multiple branches.

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found ao

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found argparse

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found bee

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found busted

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found cc-tweaked

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found cocos4.0

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found devilspie2

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found dkjson

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found dontstarve

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found fenster

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found fivem

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found garrysmod

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found halion

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found lapis

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found lldebugger

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found lmathx

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found love-nuklear

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found love2d

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found lovr

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found lpeg

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found lua-cjson

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found luaecs

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found luafilesystem

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found luaharfbuzz

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found lualogging

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found luasocket

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found luassert

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found luaunit

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found luazip

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found luvit

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found lzlib

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found md5

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found minetest

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found mirai

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found moneymoney

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found moonloader

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found nodemcu-esp32

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found nodemcu-esp8266

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found openresty

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found penlight

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found powder-toy

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found RavenscriptIDEA

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found RavenscriptIDEA_withRavenM

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found REFramework-LLS

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found skynet

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found slnunicode

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found smbx2-lunalua

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found starfallex

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found StormworksAddonLua

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found tex-lualatex

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found tex-lualibs

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found tex-luametatex

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found tex-luatex

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found toml-edit

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found transformice

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found trilogyloader

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found TTSLua

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found umbrella

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found unbound-api

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found xmake

[2024-11-13 12:15:26] |  VERBOSE  |    Addon Manager   | Found yue

[2024-11-13 12:15:26] |    WARN   |         Git        | Failed to pull LLS-Addons!

[2024-11-13 12:15:26] |   ERROR   |     Filesystem     | Unable to resolve nonexistent file 'vscode-userdata:/c:/Users/c/AppData/Roaming/VSCodium/User/globalStorage/sumneko.lua/addonManager/addons/garrysmod/module'

[2024-11-13 12:15:27] |   ERROR   |     Filesystem     | Unable to resolve nonexistent file 'vscode-userdata:/c:/Users/c/AppData/Roaming/VSCodium/User/globalStorage/sumneko.lua/addonManager/addons/garrysmod/module'

[2024-11-13 12:15:32] |   DEBUG   |       WebVue       | Workspace Open: true

[2024-11-13 12:15:32] |   DEBUG   |     Filesystem     | Created directory at "/C:/Users/c/AppData/Roaming/VSCodium/User/globalStorage/sumneko.lua/addonManager"

[2024-11-13 12:15:32] |  VERBOSE  |       Command      | Executing "getAddons" ({"command":"getAddons","data":{"page":1}})

[2024-11-13 12:15:32] |   ERROR   |     Filesystem     | Unable to resolve nonexistent file 'vscode-userdata:/c:/Users/c/AppData/Roaming/VSCodium/User/globalStorage/sumneko.lua/addonManager/addons/garrysmod/module'

[2024-11-13 12:15:32] |   ERROR   |     Filesystem     | Unable to resolve nonexistent file 'vscode-userdata:/c:/Users/c/AppData/Roaming/VSCodium/User/globalStorage/sumneko.lua/addonManager/addons/garrysmod/module'

[2024-11-13 12:16:33] |  VERBOSE  |       Command      | Executing "disable" ({"command":"disable","data":{"name":"garrysmod"}})

[2024-11-13 12:16:33] |    WARN   |        Addon       | "garrysmod" is already disabled

[2024-11-13 12:16:33] |   ERROR   |     Filesystem     | Unable to resolve nonexistent file 'vscode-userdata:/c:/Users/c/AppData/Roaming/VSCodium/User/globalStorage/sumneko.lua/addonManager/addons/garrysmod/module'

[2024-11-13 12:16:33] |   ERROR   |     Filesystem     | Unable to resolve nonexistent file 'vscode-userdata:/c:/Users/c/AppData/Roaming/VSCodium/User/globalStorage/sumneko.lua/addonManager/addons/garrysmod/module'

Start with the addon manager's handling of the .luarc.json workspace.library path and the getAddons, install, and disable entry points described in the report. Reproduce the Windows case with ${addons} while no addons are installed, then verify that the addon shows an Install button and can be installed without the nonexistent-path error.

Written by the indexing model from the issue text.