[Bug]: Company inauguration date should use calendar year in wallclock mode

[zephyris]

Version of OpenTTD

14.0-RC3

Expected result

Company inauguration date, similar to eg. vehicle design dates, should probably always be displayed as calendar year.

Actual result

In wallclock mode, inauguration time is in minutes(?) with no units, and looks quite weird.

Steps to reproduce

1. Set the time setting to wallclock mode
2. Start a new game and look at the company information window

[frosch123]

Calendar year is of little use, if calendar time is stopped.
I think it would make sense to display both:

1955 (period 1)

[2TallTyler]

Both would probably be the best player experience, yes. The calendar year of inauguration is not stored in the company (it was converted to economy year, which in calendar timekeeping mode is kept synced with the calendar), so it will need to be added, similar to what we did with #11124.