Update Excalidraw base to latest version

[AlphaCraft9658]

The version of the Excalidraw base appears to be fairly outdated. A lot of the new features don't work properly, and some of my diagrams created with Excalidraw directly don't work with this specific whiteboard application. It's cool this exists, but it really doesn't quite look as more recent versions of Excalidraw do.

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• Upon finishing, open a new issue to re-base again for next Nextcloud major cycle

[juliusknorr]

There is a new release finally on npm now. To be continued in #407