core: frontend: fix tooltip typo

[ES-Alexander]

Fixes #2511

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@dgudiel FYI text is almost always stored as-is in a source file, so if you run into issues like this and want to submit a fix for them then I'd recommend

0. creating a fork of the BlueOS repository (only need to do this once)
1. searching the repository for the problematic text, to find the file it's in
2. updating the master branch (in your fork) to be in-line with the latest state (using the "Sync fork" button)
3. creating a new branch from that point
4. going to the file you found earlier, in your fork
5. clicking the "Edit this file" pencil in the top right corner of GitHub's file viewer
6. editing the text to what you think it should be
7. pressing "Commit" in the top right corner
8. returning to the "Code" tab of your fork
9. creating a Pull Request with your changes
10. specifying which issue number it fixes (if there is one), so it gets closed automatically when the PR is merged