only validate SMTP_FROM if necessary

[stefan0xC]

#5438 seems to break setups by always requiring smtp_from to be a valid email, even if mail is disabled

reverted part of the change to fix #5441

[BlackDex]

Thanks, i overlooked that _enable_smtp could be true even if those items were not set.

[stefan0xC]

Yeah, I mean we might want to switch it so that it's generated from either of those option being set, but I'm not sure if this would break things. I have not tested it but I think it might just work. I mean, if you have saved the config.json with mail disabled, you'd probably also have to also enable it manually after configuring your SMTP settings but since it's the first option people who configure stuff via the /admin panel would probably see it, so this should be fine.

edit: oh, except that for people that have _enable_smtp already enabled we still could not remove this check, since they would then face the same issue.

[BlackDex]

I think it's more that we want someone to disable smtp while keeping there settings. Useful if your SMTP provider is offline for some reason.

[stefan0xC]

Ah, right. I also tend to forget how generated works (and probably meant auto). But this probably wouldn't work without breaking things.