fix: font not rendering on backend (replace node-canvas with `@napi…

…-rs/canvas`)

Fixes font not rendering on backend due to a bug in node-canvas v2.11.2.
See: Automattic/node-canvas#2285

Couldn't downgrade to v2.10.2 due to build issues on Windows.
See: Automattic/node-canvas#1773 (comment)

R

v3.0.0 of node-canvas will remove node-pre-gyp which should make it a bit easier to install?
See: https://github.com/Automattic/node-canvas/releases/tag/v3.0.0-rc2