fastboot:flashing_unlock does not handle code_url

[amartinz]

fastboot:oem_unlock: allows providing a code_url to specify a link to follow for instructions regarding how to obtain a code to unlock the bootloader.

fastboot:flashing_unlock: does the same as fastboot:oem_unlock: but does not allow providing a code_url according to action.schema.yml.

[NeoTheThird]

Is it even possible to supply a code to it? Maybe we simply haven't had a device that used flashing unlock and needed a code yet.

[amartinz]

I wanted to abuse that feature to show a link with instructions of how to unlock the bootloader.

so maybe should be renamed to link to match existing actions allowing to open an url?

[NeoTheThird]

That would be useful. But cave: That is not all that code_url does for fastboot:oem_unlock. It actually expects the user to obtain and enter a code. On devices that do not need that code, it would not work. So we should implement an instructions link for both of them.