Confusing terms “Validity” vs “Expires” with captive portal vouchers

[itkfm]

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Is your feature request related to a problem? Please describe.

The English terms “Validity” and “Expires in” basically mean the same things.
This makes generating captive portal vouchers a confusing task because you have to figure out which is which first.

Describe the solution you like

Regarding the Captive Portal: Vouchers page (/ui/captiveportal/voucher):

I would like to have the labels in the “Generate vouchers” dialog (which is opened by the “Create vouchers” button) to have distinct names that make it clear which one is the validity of the voucher code itself and which one designates the validity of the session.

Furthermore, I’d prefer if the overview page didn’t mix terminology all the time.
At the moment, a voucher with no “Expires at” can still have its “State” saying “expired”.

Describe alternatives you considered

It would already be helpful if this could be looked up in the docs.
As-is, https://docs.opnsense.org/manual/captiveportal.html doesn’t even mention the patterns “expir…” or “valid…”.

Additional context

[AdSchellevis]

moved to docs tracker, the function seems to be doing what it should do, but documentation is limited.

Validity marks the total amount of time the token accounts for (e.g. you're allowed to use internet for four hours), where expires sets a hard limit to that right (..but you're not allowed to use the internet after 7 days from now).