Fix bubbling of events originating in user shadow dom

[WorldSEnder]

When there is no explicit portal into the shadow, we should bubble up to the host element of the shadow root and continue. This fixes custom elements internally using open shadow DOM.

Description

Fixes #2624

Checklist

• I have run cargo make pr-flow
• I have reviewed my own code
• I have added tests

[github-actions]

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[github-actions]

Size Comparison

examples	master (KB)	pull request (KB)	diff
boids	173.225	173.419	+0.194
contexts	110.501	110.690	+0.189
counter	87.184	87.386	+0.202
counter_functional	87.746	87.943	+0.197
dyn_create_destroy_apps	90.268	90.436	+0.168
file_upload	103.117	103.317	+0.200
function_memory_game	167.623	167.814	+0.191
function_router	353.295	353.348	+0.053
function_todomvc	162.514	162.717	+0.203
futures	226.903	227.100	+0.196
game_of_life	108.204	108.423	+0.219
inner_html	83.682	83.881	+0.199
js_callback	113.266	113.459	+0.193
keyed_list	196.121	196.312	+0.191
mount_point	86.707	86.903	+0.196
nested_list	116.218	116.408	+0.190
node_refs	90.077	90.274	+0.197
password_strength	1539.661	1539.890	+0.229
portals	97.286	97.481	+0.195
router	319.138	319.216	+0.078
simple_ssr	500.580	500.780	+0.200
ssr_router	428.699	428.905	+0.206
suspense	111.021	111.217	+0.196
timer	89.899	90.103	+0.203
todomvc	143.865	144.064	+0.199
two_apps	87.772	87.970	+0.197
webgl	87.358	87.561	+0.202