Incorrect power button handling in Game mode

[thegreatGreenstar]

Your system information

• Steam client version: 1763795278
• SteamOS version: 3.7.17
• Opted into Steam client beta?: [Yes/No]
• Opted into SteamOS beta?: [Yes/No]
• Have you checked for updates in Settings > System?: [Yes/No]

Please describe your issue in as much detail as possible:

Describe what you expected should happen and what did happen.
When a power button (such as on a PC case) is used instead of an expected one, nothing happens
For example:

What should happen instead is that the power menu is opened (to be specific, image attached):

Additional relevant information:
This button is detected and fully functions in desktop mode, with the default behavior of immediate shutdown without countdown if pressed. (While this behavior isn't optimal for future parity, changing such exceeds scope of this issue.)

Steps for reproducing this issue:

1. Use SteamOs such that it is tied to a PC case wherein physically disabling power to it removes power such that steamOs would immediately cease function per power loss. (Though unsupported the easiest and thus method I recommend to do this is simply install SteamOs on a PC)
2. At any point once intro cutscene is over and outside of Desktop mode, press the power button.
3. Nothing happens.