Backport #10486: Catch exception if git is not installed

[mergify]

This is a trivial pr that should fix a bug in cabal init when git is not installed.

---

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
• The documentation has been updated, if necessary.
• Manual QA notes have been included.
• Tests have been added.

QA Notes

cabal init should work correctly even if git is not installed. This can be tested by running the following commands in an empty directory and answering the prompts:

mkdir /tmp/bin
ln -s "$(which ghc)" "$(which cabal)" /tmp/bin/
PATH=/tmp/bin/ cabal init
```<hr>This is an automatic backport of pull request #10486 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of e7bc62b has failed:

On branch mergify/bp/3.12/pr-10486
Your branch is up to date with 'origin/3.12'.

You are currently cherry-picking commit e7bc62be2.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   cabal-install/src/Distribution/Client/Init/NonInteractive/Heuristics.hs
	new file:   cabal-testsuite/PackageTests/Init/init-without-git.out
	new file:   cabal-testsuite/PackageTests/Init/init-without-git.test.hs
	new file:   changelog.d/pr-10486

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   cabal-install/src/Distribution/Client/Init/Types.hs

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[geekosaur]

mm, right, this one's pretty violent although technically cabal-install API is safe to change. Nemmind