fix: ignore closed PRs in update workflow when creating a new PR

[oxcabe]

Description

This PR fixes the docs updating workflow not opening a new PR if the actions-generate-docs branch has already a closed PR related to it.

Additional context

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What is the purpose of this pull request?

• [x] Bug fix
• [ ] New Feature
• [ ] Documentation update
• [ ] Other

Before submitting the PR, please make sure you do the following:

• [x] Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• [x] Follow the Conventional Commits v1.0.0 standard for PR naming (e.g. feat(examples): add hello-world example).
• [x] Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• [x] Ideally, include relevant tests that fail without this PR but pass with it.

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Name	Status	Preview	Comments	Updated (UTC)
docs	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jan 8, 2024 0:40am