Phosh: lockscreen not shown on startup

Describe your issue

The Phosh lockscreen should be shown after starting the phone for improved security.\

Not locking the screen at boot allows to bypass a locked phone by simply restarting it, since the lock is not shown at boot.
A locked phone can be easily restarted by long pressing on the power button to shut it down and pressing it again to turn it on.

What's the expected behaviour?

The Phosh lockscreen is shown after starting the phone

What's the current behaviour?

The Phosh lockscreen is not shown after starting the phone

How to reproduce your issue?

Boot a pmos installation with Phosh

What device are you using?

pine64-pinephone v1.1 Braveheart

On what postmarketOS version did you encounter the issue?

• edge (master branch)
• stable (v20.05 branch)

On what environment did you encounter the issue?

Phone environments

• Phosh
• Plasma Mobile
• Sxmo

How did you get postmarketOS image?

• from https://images.postmarketos.org
• I built it using pmbootstrap
• It was preinstalled on my device

What's the build date of the image? (in dd-mm-yyyy format)

27-09-2020 (commit 905a5ce3)

Additional information