fix(files): Focus filename input in new-node dialog when opened

[susnux]

• Resolves: [Bug]: New file name modal does not always set focus #43659

Summary

Always focus the filename input when the dialog is opened

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[susnux]

/backport to stable29

[susnux]

/backport to stable28

[ChristophWurst]

Makes sense 🙏

[szaimen]

Tested and seems to work :)

[kesselb]

Thank you 👍

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