HLS's fourmolu plugin does not respect `import-grouping: by-scope-then-qualified`

### Your environment

Which OS do you use?
```
$ uname -a
Darwin *** 24.6.0 Darwin Kernel Version 24.6.0: Mon Jul 14 11:30:30 PDT 2025; root:xnu-11417.140.69~1/RELEASE_ARM64_T6020 arm64
```
Which version of GHC do you use and how did you install it?
```
$ which ghc
/Users/bf/.ghcup/bin/ghc
$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 9.10.2
```
How is your project built (alternative: link to the project)?
[link](https://github.com/bfeitknecht/impli)

Which LSP client (editor/plugin) do you use?
Zed with the Haskell extension
Which version of HLS do you use and how did you install it?
```
$ haskell-language-server-wrapper --version
haskell-language-server version: 2.11.0.0 (GHC: 9.10.2) (PATH: /Users/bf/.ghcup/hls/2.11.0.0/lib/haskell-language-server-2.11.0.0/bin/haskell-language-server-wrapper)
```
Have you configured HLS in any way (especially: a `hie.yaml` file)?
```json
"hls": {
"initialization_options": {
"haskell": {
"formattingProvider": "fourmolu",
"plugin": {
"fourmolu": {
"enabled": true,
"config": {
"external": true
}
},
"hlint": {
"enabled": true
}
}
}
}
}
```

### Steps to reproduce

Let `config.yaml` contain `import-grouping: by-scope-then-qualified`. Format via HLS (e.g. on save). Format with `fourmolu` binary. There is a diff.

### Expected behaviour

No diff.

### Actual behaviour

There is a diff.

### Debug information