<space> not working as leader key - the key combination (Space, -) is not a command

Describe the bug
When setting <space> (or " ") as a leader key, it does not work.
It works if I use another key (i.e. m) as a leader key.
The message I get is "the key combination (Space, D) is not a command"

To Reproduce
I disabled all the extensions apart from the VSCode Vim extension.
The minimal settings.json is the following

{
  "vim.leader": " ",
  "vim.normalModeKeyBindings": [
    {
      "before": ["<leader>", "d"],
      "commands": ["editor.action.deleteLines"]
    },
  ]
}

Expected behavior
The action is sent (with the minimal config posted above, a line is deleted)

Environment:

• Extension (VsCodeVim) version:
  1.25.2

• VSCode version:
  Version: 1.77.1
  Commit: b7886d7461186a5eac768481578c1d7ca80e2d21
  Date: 2023-04-04T23:20:37.202Z
  Electron: 19.1.11
  Chromium: 102.0.5005.196
  Node.js: 16.14.2
  V8: 10.2.154.26-electron.0
  OS: Linux x64 6.2.6-76060206-generic
  Sandboxed: No

• OS:

➜ cat /etc/os-release                           
NAME="Pop!_OS"
VERSION="22.04 LTS"
ID=pop
ID_LIKE="ubuntu debian"
PRETTY_NAME="Pop!_OS 22.04 LTS"
VERSION_ID="22.04"
HOME_URL="https://pop.system76.com"
SUPPORT_URL="https://support.system76.com"
BUG_REPORT_URL="https://github.com/pop-os/pop/issues"
PRIVACY_POLICY_URL="https://system76.com/privacy"
VERSION_CODENAME=jammy
UBUNTU_CODENAME=jammy
LOGO=distributor-logo-pop-os

Start by reproducing the issue with the minimal settings.json configuration in the VSCode Vim extension, comparing the space leader with a working letter leader. Trace the handling of the key sequence and verify the configured editor.action.deleteLines command. Done means the space-plus-d keybinding executes the action without the "is not a command" message.