feat: change icon cog into the outline version

[GretaD]

☑️ Resolves

• Fix feat: calendar icon not outline nextcloud/calendar#7225

🖼️ Screenshots

🏚️ Before	🏡 After
B	A

🚧 Tasks

• ...

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable
• 2️⃣ Backport to stable8 for maintained Vue 2 version or not applicable

[Antreesy]

IIRC the discussion was to change Cog not to outline, but to Material symbol: https://fonts.google.com/icons?icon.set=Material+Symbols&icon.size=24&icon.color=%235f6368&selected=Material+Symbols+Outlined:settings:FILL@0;wght@400;GRAD@0;opsz@24&icon.query=cog

[susnux]

Fine for main, for backport it needs a legacy fallback

[susnux]

IIRC the discussion was to change Cog not to outline, but to Material symbol

As long as we do not have nextcloud/standards#16 or similar we should still use MDI for consistency and also for common dependencies.
So yes the stretch goal is Material Symbols but as we do not have a library to use we still use MDI

[susnux]

/backport to stable8

[backportbot]

The backport to stable8 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable8
git pull origin stable8

# Create the new backport branch
git checkout -b backport/7299/stable8

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick 41a4b18e

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/7299/stable8

Error: Failed to check for changes with origin/stable8: No changes found in backport branch

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Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.