fix: Pass over product name as capability

[juliusknorr]

This is being used to set the title and should be exposed to clients and the frontend

server/apps/files/src/views/FilesList.vue

Line 489 in 9c5e464

document.title = `${this.pageHeading} - ${getCapabilities().theming?.productName ?? 'Nextcloud'}`

[juliusknorr]

/backport to stable31

[juliusknorr]

/backport to stable30

[susnux]

See also #53321

But anyways it makes sense to pass the product name as capability

[backportbot]

The backport to stable30 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable30
git pull origin stable30

# Create the new backport branch
git checkout -b backport/53339/stable30

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick 9f12d685 1d0915b3

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/53339/stable30

Error: Failed to push branch backport/53339/stable30: remote: Invalid username or password.
fatal: Authentication failed for 'https://github.com/nextcloud/server.git/'

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