poky: Remove Fedora38 from SANITY_TESTED_DISTROS

Now the obsolete config is removed from the autobuilder, we should remove
this distro from the tested list too.

(From meta-yocto rev: 59567ab18a6819ea845c9be824b203d030eb09c4)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-poky/conf/distro/poky.conf

@@ -37,7 +37,6 @@ SANITY_TESTED_DISTROS ?= " \
             ubuntu-22.04 \n \
             ubuntu-24.04 \n \
             ubuntu-24.10 \n \
-            fedora-38 \n \
             fedora-39 \n \
             fedora-40 \n \
             fedora-41 \n \