fix: do not crash findComponent if ref points to an svg element - #2983

findComponent({ ref }) only treated HTMLElement refs as DOM elements. A ref on an <svg> (or any other SVG or MathML element) was passed to createVueWrapper as if it were a component instance, and that crashes in hasSetupState:

const Comp = defineComponent({ template: '<svg ref="icon"><circle /></svg>' })
mount(Comp).findComponent({ ref: 'icon' }).exists()
// before: TypeError: Cannot read properties of undefined (reading 'devtoolsRawSetupState')
// after: false

getComponent({ ref }) threw the same TypeError instead of the usual "Unable to get component with ref ..." error. This changes the guard to instanceof Node, which find({ ref }) already uses, so every DOM element ref gets the empty wrapper that HTML element refs already get. Component refs are never nodes, so they are not affected.

• Ran: pnpm vitest run tests/findComponent.spec.ts (the new test fails on main with the TypeError and passes with the fix)
• Ran: pnpm vitest run (511 passed, 1 todo) and pnpm run test:build after a build (same result)
• Checked: pnpm run lint (no new warnings), pnpm run format-check, pnpm run vue-tsc, pnpm run tsd