The `web_workers/images` example is not being tested by any e2e
spec and therefore it's technically not necessary to fix that it uses
external resources, though in order to ensure that the Bazel builds
are hermetic and that we can eventually add e2e specs for the
web_worker/image example, we should avoid any use of external
resources.
We remove the `web-animations` polyfill in the `web_workers/animations`
example because we should try to vendor as few as possible deps. Also
the animations API is already supported by browsers we run the e2e tests
against (note here: `web_workers/animations` is currently also disabled)
PR Close#28562
Paul Gschwendtner