Cabal accepts invalid sublibrary names.

See https://github.com/phadej/cabal-sublib-bug

**Describe the bug**

Cabal parser accepts

```haskell
cabal-version: 3.8
name: cabal-sublib-bug
version: 0

library james-bond-007
default-language: Haskell2010
hs-source-dirs: src-a
build-depends: base <5
exposed-modules: A

library
default-language: Haskell2010
hs-source-dirs: src-a
build-depends: base <5
exposed-modules: B

-- note: for private libraries this is not an issue,
-- as we cannot depend on them, the field below doesn't parse
-- public libraries couldnt' be used either, but we'll catch that too late!
-- build-depends: cabal-sublib-bug:james-bond-007
```

in particular the `library james-bond-007`.

This doesn't work. We cannot use it `build-depends: cabal-sublib-bug:james-bond-007` fails to parse. But if we don't add the dependency it will fail to compile:

```
Error: [Cabal-7125]
Failed to build cabal-sublib-bug-0.
Failed to build lib:james-bond-007 from cabal-sublib-bug-0. The failure occurred during the final install step. The exception was:
Error: [Cabal-7038]
Couldn't parse the output of 'setup register --gen-pkg-config':".:1:58: \nunexpected end of input\n\n"
```

**To Reproduce**

See https://github.com/phadej/cabal-sublib-bug

**Expected behavior**

I think `.cabal` parser should reject the invalid library name early.

**Additional context**

I think, that the (private) library names were restricted to the same rules as library/package names, as we could use them unqualified (just `james-bond-007` - but that looks like package id - there's a version). In latest `cabal-version`s we can only use qualified names (`cabal-sublib-bug:james-bond-007`), so maybe it would be possible to relax library names in some future cabal spec version. But I think it's not worth the subtleties.

Now, with *public* sublibraries, it's possible that someone accidentally creates an unusable public library.
The build failure of failing to register (see above) is confusing.

I found this issue because I was creating (private) test library components, like `test-01`, `test-02` etc and not yet using them, and spent good chunk of time wondering what's wrong.