homescreen: Fix systemd service template for sed

For the record if was tested with oniro using:

SERVICE_EXEC_START_PARAMS:pn-ivi-homescreen-debug = "--f --a=/usr/share/gallery --t=DMZ-White"
SERVICE_UNIT:pn-ivi-homescreen-debug = "Requires=weston.service\nAfter=weston.service\n"
SERVICE_USER_GROUP:pn-ivi-homescreen-debug = "User=weston\nGroup=weston"
SERVICE_ENVIRONMENT:pn-ivi-homescreen-debug = "Environment=HOME=/home/weston\nEnvironment=XDG_RUNTIME_DIR=/run/user/1000"

Forwarded: https://github.com/meta-flutter/meta-flutter/pulls?q=author%3Arzr Relate-to: https://github.com/meta-flutter/meta-flutter/pull/71 Relate-to: https://booting.oniroproject.org/distro/oniro/-/merge_requests/541 Signed-off-by: Philippe Coval philippe.coval@huawei.com