cxx_builtin_include_directories package resolution uses deprecated function

### Description of the bug:

The logic which expands package directories for `cxx_builtin_include_directories` uses the deprecated `Label.relative` function [here](https://github.com/bazelbuild/bazel/blob/935bd263ec5912469d7d0f0abe54efc071018a32/src/main/starlark/builtins_bzl/common/cc/cc_toolchain_provider_helper.bzl#L130)

### Which category does this issue belong to?

C++ Rules

### What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

According to @Wyverald, this should cause issues when you have a package in a repo with `@` (for example, `"%package(@repo//foo/bar)%/baz/quux") when Bzlmod is enabled.

### Which operating system are you running Bazel on?

_No response_

### What is the output of `bazel info release`?

_No response_

### If `bazel info release` returns `development version` or `(@non-git)`, tell us how you built Bazel.

_No response_

### What's the output of `git remote get-url origin; git rev-parse HEAD` ?

_No response_

### Is this a regression? If yes, please try to identify the Bazel commit where the bug was introduced.

_No response_

### Have you found anything relevant by searching the web?

_No response_

### Any other information, logs, or outputs that you want to share?

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Start in src/main/starlark/builtins_bzl/common/cc/cc_toolchain_provider_helper.bzl at the package-directory expansion that uses Label.relative. Check the referenced package form, such as "%package(@repo//foo/bar)%/baz/quux", with Bzlmod enabled. Done means package resolution no longer relies on the deprecated function and the example works.

Written by the indexing model from the issue text.