[FIX] web: do not deploy services twice

Since 671a5471, services are deployed twice in the backend:
once by the webclient (as it is a ServiceProvider), and once by the
env (which now deploys the services to make them directly available
for each Owl component of the component tree). As a consequence,
some services perform twice some operations (e.g. the mail service
fetches twice the /mail/init_messaging route, the crash manager
service displays twice the tracebacks...).

This commit fixes the issue by making the webclient directly use
services from the env, instead of deploying them a second time.

Part of 2183810

closes odoo/odoo#44301

Signed-off-by: Lucas Perais (lpe) <lpe@odoo.com>