[frontend] update sharp to latest to avoid docker build issue on M1

Building the frontend container image on an Apple M1 would result in
the following error during docker build:

    15.56 > Build error occurred
    15.56 [Error: ENOENT: no such file or directory, copyfile '/app/node_modules/sharp/build/Release/sharp-darwin-arm64v8.node' -> '/app/.next/standalone/node_modules/sharp/build/Release/sharp-darwin-arm64v8.node'] {
    15.56   errno: -2,
    15.56   code: 'ENOENT',
    15.56   syscall: 'copyfile',
    15.56   path: '/app/node_modules/sharp/build/Release/sharp-darwin-arm64v8.node',
    15.56   dest: '/app/.next/standalone/node_modules/sharp/build/Release/sharp-darwin-arm64v8.node'
    15.56 }

Updating sharp to v0.33.x avoids this problem, as that version includes
pre-built sharp binaries for various platforms, see
https://sharp.pixelplumbing.com/changelog#v0330---29th-november-2023