Breaking change in importing packages?

**Describe the bug**
I installed cabal-install from source and noticed a breaking change. I took the test from #8686 and created a similar test that shows the problem.

```
$ pwd
/.../cabal/cabal-testsuite/ProjectTests/Import/PackageGroups
$ tree
.
├── cabal-configs
│   ├── pkg-groups
│   │   └── dep1-dep2.config
│   └── pkgs.config
├── cabal.out
├── cabal.project
├── cabal.test.hs
├── dep1
│   ├── dep1.cabal
│   └── Dep1.hs
├── dep2
│   ├── dep2.cabal
│   └── Dep2.hs
├── Lib.hs
└── main.cabal
```

Stepping through the indirection of imports:

```
$ cat cabal.project
import: cabal-configs/pkgs.config

packages:
./
```

```
$ cat cabal-configs/pkgs.config
import: cabal-configs/pkg-groups/dep1-dep2.config
```

```
$ cat cabal-configs/pkg-groups/dep1-dep2.config
packages:
./dep1/
, ./dep2/
$
```

In the reproduction, if I import the packages in 1-hop then we're good but in 2-hops we break (when we didn't before).

```cabal
-- Importing packages in one hop works. Uncomment the line below to see that.
-- import: cabal-configs/pkg-groups/dep1-dep2.config

-- Importing the same packages in two hops works with cabal-install-3.8.1.0 but fails now.
import: cabal-configs/pkgs.config

packages:
./
```

**To Reproduce**
First off with v3.8.1.0 (this works):

```
$ ~/.ghcup/bin/cabal clean --project-file=./cabal.project
$ ~/.ghcup/bin/cabal build all --dry-run --project-file=./cabal.project
Resolving dependencies...
Build profile: -w ghc-9.2.5 -O1
In order, the following would be built (use -v for more details):
- dep1-0.1 (lib) (first run)
- dep2-0.1 (lib) (first run)
- main-0.1 (lib) (first run)
$ ~/.ghcup/bin/cabal --version
cabal-install version 3.8.1.0
compiled using version 3.8.1.0 of the Cabal library
```
Then with v3.9.0.0 (this fails):

```
$ ~/.cabal/bin/cabal clean
$ ~/.cabal/bin/cabal build all --dry-run --project-file=./cabal.project
cabal-configs/cabal-configs/pkg-groups/dep1-dep2.config:
withBinaryFile: does not exist (No such file or directory)
$ ~/.cabal/bin/cabal --version
cabal-install version 3.9
compiled using version 3.9.0.0 of the Cabal library
```

From the error report, cabal has repeated the first part of the path.

```diff
- cabal-configs/pkg-groups/dep1-dep2.config
+ cabal-configs/cabal-configs/pkg-groups/dep1-dep2.config
```

**Expected behavior**
I like Dhall's stance on imports. Can we do something like that?

> "The import resolution phase replaces all imports with the expression located at that import, transitively resolving imports within the imported expression if necessary.
> "SOURCE: [Import Resolution Judgment](https://github.com/dhall-lang/dhall-lang/blob/master/standard/imports.md#import-resolution-judgment)

**System information**
- Ubuntu 22.04.1 LTS

```
$ cabal --version
cabal-install version 3.8.1.0
compiled using version 3.8.1.0 of the Cabal library
$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 9.2.5
```