[13740] Add afunction that checks for repeated -I paths (issue #78) (backport #429)

[mergify]

Description

Added a function that checks if the paths included with the -I function have already been added, and skips them if so. This solves issue #78, and was suggested by the original author. I had to update a couple of terms to the new notation, so we should be careful with backports.

@Mergifyio backport 3.3.x 2.5.x 2.1.x

Fixes #78

Contributor Checklist

• Commit messages follow the project guidelines.

• 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

• 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.

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This is an automatic backport of pull request #429 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 5f95b79 has failed:

On branch mergify/bp/2.1.x/pr-429
Your branch is up to date with 'origin/2.1.x'.

You are currently cherry-picking commit 5f95b79.
  (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)

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

no changes added to commit (use "git add" and/or "git commit -a")

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