Fix element with clipPath and shadow svg serialization

[phil-r]

This fixes the issue for the example provided in #6651, but sadly it breaks other tests and I'm not sure how I should approach this.

Before:

https://codesandbox.io/s/hopeful-lake-vvm9n?file=/src/index.js

After:

https://codesandbox.io/s/pensive-visvesvaraya-bs738?file=/index.html

I would be happy if you could provide some guidance into how broken tests can be fixed, or if my approach is completely wrong, thanks.

[asturur]

i understand the issue, the shadow-filter should be applied on the clipped object an not vice versa.
I m just unsure how to deal with it, it was a bit complicated to have clipPath working correctly in svg export

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.