cabal init --overwrite: openFile: app/Main.hs: does not exist (No such file or directory)

**Describe the bug**
cabal init --overwrite: openFile: app/Main.hs: does not exist (No such file or directory)

**To Reproduce**
Steps to reproduce the behavior:

```
$ cabal init -n
[...]
$ cabal init -n --overwrite

Log: Guessing dependencies...

Log: Using cabal specification: 3.0

Warning: unknown license type, you must put a copy in LICENSE yourself.

Log: CHANGELOG.md already exists. Backing up old version in CHANGELOG.md.save0

Log: Overwriting file CHANGELOG.md...

Log: /tmp/tmp.ndqJzZ9Tz3 already exists. Backing up old version in /tmp/tmp.ndqJzZ9Tz3.save0

Log: Overwriting directory .//tmp/tmp.ndqJzZ9Tz3...
/tmp/tmp.ndqJzZ9Tz3/app/Main.hs: openFile: does not exist (No such file or directory)
```

Please use version-prefixed commands (e.g. `v2-build` or `v1-build`) to avoid ambiguity.

**Expected behavior**
no error, the existing .cabal file is overwritten

**System information**
- cabal 3.8.1.0-rc1

cc @emilypi @ptkato