Fix bgld Docker entrypoint command handling

[manuelsampedro1]

Summary

• fix the entrypoint root-drop guard to match the actual bgl_oneshot command used by this image
• remove the stray whitespace after the Dockerfile line-continuation for ca-certificates so the package install list is parsed correctly

Validation

• /bin/sh -n docker-entrypoint.sh
• git diff --check
• checked that stale btc_oneshot / malformed ca-certificates \\ patterns are gone with rg
• smoke-tested the root path with stubbed id, chown, and gosu commands; the entrypoint now delegates bgl_oneshot through gosu BGL

[MyTH-zyxeon]

Review-assist note for the Bitgesell #81 improvement lane.

I checked the public PR body and diff. This is a small operational Docker reliability fix:

• updates the root-drop guard from the stale btc_oneshot command to the image's actual bgl_oneshot entrypoint path
• fixes the ca-certificates package continuation line so the install list is parsed consistently
• keeps the change away from wallets, RPC credentials, consensus logic, and live chain actions

Suggested maintainer checks before merge:

• build the image from this branch and run /bin/sh -n docker-entrypoint.sh
• smoke-start the container as root with bgl_oneshot and confirm it re-execs through gosu BGL
• start it with --user to confirm the non-root path still runs as invoked
• run a Dockerfile parse/build check that covers the ca-certificates line-continuation fix

From the public patch shape, this looks like a useful low-risk infrastructure/reliability candidate for the #81 improvement queue.