Bug 467269

SUMMARY
The changes for Bug 420928 introduced LC_PAGE into the System Settings:

https://invent.kde.org/plasma/plasma-workspace/commit/73bfdcff3d7d16e648aaf9ea7630a3967376412e
https://invent.kde.org/plasma/plasma-workspace/commit/c7c2a3a85e5b7f74dcb2eadc35defe9e4b55c737

* they talk about paper size, not page size
* seem to read from LC_PAPER environment variable? (maybe I didn't understand the code correctly)
* write LC_PAGE to ./config/plasma-localerc instead of LC_PAPER

When I login to the desktop, open a console and execute "locale" I get LC_PAPER set to the default specified by LANG, instead of the KDE setting.

System Settings should either write LC_PAPER or write LC_PAPER & LC_PAGE into the configuration file. But as far as I can tell LC_PAGE is *not* an official locale category and should be dropped.

STEPS TO REPRODUCE
1. open System Settings
2. select a paper size different from the locale default (I selected "Suomi", i.e. paper size from finnish locale)
3. log out and in again
4. open konsole
5. run "locale" command

OBSERVED RESULT
# before change:
$ cat .config/plasma-localerc 
[Formats]
LANG=en_US.UTF-8
LC_ADDRESS=fi_FI.UTF-8
LC_MEASUREMENT=fi_FI.UTF-8
LC_MONETARY=fi_FI.UTF-8
LC_NAME=fi_FI.UTF-8
LC_TELEPHONE=fi_FI.UTF-8
LC_TIME=en_GB.UTF-8

# after change
$ cat .config/plasma-localerc 
[Formats]
LANG=en_US.UTF-8
LC_ADDRESS=fi_FI.UTF-8
LC_MEASUREMENT=fi_FI.UTF-8
LC_MONETARY=fi_FI.UTF-8
LC_NAME=fi_FI.UTF-8
LC_PAGE=fi_FI.UTF-8
LC_TELEPHONE=fi_FI.UTF-8
LC_TIME=en_GB.UTF-8

$ locale
LANG="en_US.UTF-8"
....
LC_PAPER="en-US.UTF-8"

EXPECTED RESULT
$ locale
LANG="en_US.UTF-8"
...
LC_PAPER="fi_FI.UTF-8"

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Fedora Linux 37
KDE Plasma Version: 5.27.2
KDE Frameworks Version: 5.103.0
Qt Version:  5.15.8