[23094] Escape folder separator in generated CMakeLists.txt (backport #466)

[mergify]

Description

Fixes a bug in Windows when generating CMakeLists.txt

@Mergifyio backport 4.0.x 3.3.x 2.5.x 2.1.x (not sure if all, only those supporting relative dir generation)

Contributor Checklist

• Commit messages follow the project guidelines.

• N/A: Tests that thoroughly check the new feature have been added/Regression tests checking the bug and its fix have been added; the added tests pass locally

  • Affects only Windows, where we currently have no CI

• N/A: New feature has been documented/Current behavior is correctly described in the documentation.

• Applicable backports have been included in the description.

Reviewer Checklist

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• Check CI results: changes do not issue any warning.
• Check CI results: failing tests are unrelated with the changes.

---

This is an automatic backport of pull request #466 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 9bc63a8 has failed:

On branch mergify/bp/3.3.x/pr-466
Your branch is up to date with 'origin/3.3.x'.

You are currently cherry-picking commit 9bc63a8.
  (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:   src/main/java/com/eprosima/fastdds/idl/templates/SwigCMake.stg
	modified:   src/main/java/com/eprosima/fastdds/solution/Project.java

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   src/main/java/com/eprosima/fastdds/fastddsgen.java
	both modified:   src/main/java/com/eprosima/fastdds/idl/templates/CMakeLists.stg

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