feat(joint-vitest-plugin-mock-svg): Add new plugin

[zbynekstara]

Description

Adds a Vitest plugin to mock SVG global constants required for JointJS testing. Importing this plugin will solve issues such as #2824.

import { defineConfig } from 'vitest/config';
import mockSVG from '@joint/vitest-plugin-mock-svg'

export default defineConfig({
  plugins: [mockSVG()],
})

This PR includes React and Vue E2E tests, which can be run via yarn run test (needs yarn install + yarn run dist on the package + yarn run dist on joint-core).

Note

If you get error Failed to resolve entry for package "@joint/vitest-plugin-mock-svg". The package may have incorrect main/module/exports specified in its package.json. [plugin externalize-deps], it means that you have not run yarn run dist inside the joint-vitest-plugin-mock-svg package. See above for instructions