proxy settings is not applied to services

snap version 2.44~pre1
core 18

Precondition: snap set system proxy.http=blablabla

Expected result:
 proxy setting is available to applications and services
Actual result:
 proxy is only available to applications
 no daemon has proxy settings applied

Closer investigations shows following:
snapd will update /etc/environment with http_proxy value once config is applied
this is then picked by applications, when they are started
But services do not source /etc/environment at all and ignore the configuration.

Quick test shows why, service file is missing line: 'EnvironmentFile=-/etc/environment'

$ systemctl cat snap.hello-world.env-daemon.service
[Unit]
# Auto-generated, DO NOT EDIT
Description=Service for snap application hello-world.env-daemon
Requires=snap-hello\x2dworld-x6.mount
Wants=network.target
After=snap-hello\x2dworld-x6.mount network.target
X-Snappy=yes

[Service]
ExecStart=/usr/bin/snap run hello-world.env-daemon
SyslogIdentifier=hello-world.env-daemon
Restart=no
WorkingDirectory=/var/snap/hello-world/x6
TimeoutStopSec=30
Type=oneshot

[Install]
WantedBy=multi-user.target

Once service file is updated with 'EnvironmentFile=-/etc/environment' all works as expected.
We likely need to update service file template, otherwise there is different behaviour between apps and daemons