fix: Remove docker.service dependency from sysbox-mgr

sysbox-mgr doesn't require dockerd to be running at startup.
Removing this dependency allows sysbox to be installed and started
before dockerd, avoiding potential deadlock during early boot.

Author: kvinwang

scripts/sysbox-mgr.service

@@ -1,8 +1,6 @@
 [Unit]
 Description=Sysbox Manager
 Documentation=https://github.com/nestybox/sysbox
-After=docker.service
-Wants=docker.service
 
 [Service]
 Type=simple