build(deps): bump Externals/imgui from 1d942eb to 3109131

Bumps [Externals/imgui](https://github.com/ocornut/imgui) from `1d942eb` to `3109131`.
- [Release notes](https://github.com/ocornut/imgui/releases)
- [Commits](ocornut/imgui@1d942eb...3109131)

---
updated-dependencies:
- dependency-name: Externals/imgui
  dependency-version: 3109131a882daec56a530aff540416983c240443
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]