This PR fixes an issue where in some environments where `HTMLElement` is
not
available (on the server) and AG Grid is used, we crashed.
This happens because the `HTMLElement` is polyfilled to an empty object.
This means that the `typeof HTMLElement !== 'undefined'` check passed,
but the `v instanceof HTMLElement` translated to `v instanceof {}` which
is invalid and resulted in a crash...
This PR solves it by checking for exactly what we need, in this case
whether the `outerHTML` property is available.
Alternatively, we could use `return v?.outerHTML ?? v`, but not sure if
that's always safe to do.
Fixes: #3471
Robin Malfait
63daa86b61