Performance: adding an `import` retriggers a long "Processing"

### Your environment
Which OS do you use? Linux / NixOS
Which version of GHC do you use and how did you install it? GHC `9.10.1`, installed using nix/nixpkgs.
How is your project built (alternative: link to the project)? A custom build system based on nix.

Which LSP client (editor/plugin) do you use? Neovim builtin lsp
Which version of HLS do you use and how did you install it? `2.9.0.0`
Have you configured HLS in any way (especially: a `hie.yaml` file)?

My `hie.yaml` contains:

```
cradle:
bios:
shell: "nix run .#haskell_hie_bios"
```

And the nix target `haskell_hie_bios` lists all the required build flags used by GHC to build one monolithic packages composed of 1089 modules. It also contains the listing of the 1089 modules, eg:

```
-XFoo
-XBar
-ipath/to/src
-ipath/to/src2
-ffoo
path/to/src/Module/Module.hs
path/to/src2/Module2/Module2.hs
```

### Steps to reproduce

I don't know how to reproduce that outside of our large codebase, but what do I observe:

- I've turned `--debug --log /path/to/a/file.log`
- I start my editor (neovim, note that my collegues using vscode observes the same problem), load a file (for the example, I loaded a file which is at the end of the dependency tree, it contains a `main` function and no other module depends on that module).
- After a bit of time, I can see:
```
2024-11-02T08:45:19.194755Z | Debug | Finished: C:GetHieAst:/home/guillaume/jinko/jinko/simwork/core-webservice/app/Local/Main.hs Took: 2m34s
```

In the log.
- I can edit my file, do some change, that's super reactive. I can add function, hover for documentation, go to definition, everything is smooth and fast. Code action works fine, everything works great.
- If I go to the top of the module, `import` section, I can add/remove symbols in the currently existing imported module, but if I add (or remove) an `import` statment, it starts `Processing` for a long time. For example, after adding `import Data.Functor` on top of my file, I can see `Processing` and `Indexing` (and actually, a few, sometime 2 or 3 `Processing`) and for a few seconds, HLS is not reactive anymore. Here is the message in the log:

```
2024-11-02T08:48:35.124980Z | Debug | Finished: C:GetHieAst:/home/guillaume/jinko/jinko/simwork/core-webservice/app/Local/Main.hs Took: 36.24s
2024-11-02T08:48:35.125044Z | Debug | Finished: C:GetHieAst:/home/guillaume/jinko/jinko/simwork/core-webservice/app/Local/Main.hs Took: 36.24s
2024-11-02T08:48:35.125125Z | Debug | Finished: C:GetHieAst:/home/guillaume/jinko/jinko/simwork/core-webservice/app/Local/Main.hs Took: 36.24s
```

(I'm surprised by the 3 lines of log. but note the `36s`.). Note that there may be another problem with my setup or with HLS because `36s` is a really long time, but the original problem is that I'm wondering why it is "re-processing" everything.

### Expected behavior

Should not `Processing` for `40s` when I had an import. I can understand that it may invalidate the build tree by adding an `import`, but this file being at the End of the build hierarchy, no module depends on it, so it is surprising.

### Debug information

Sorry, I'm opening this issue without much details, in order to start tracking the problem. I'll try to investigate a bit more (especially, it looks like the issue is new at work, so I may be able to find which update triggered it.)