Revert "Python Classroom: Share disk size declaration between disk and live"

This reverts commit 093733933f.

    BuildError: Failed to parse kickstart file '.../fedora-disk-python-classroom.ks' : The following problem occurred on line 12 of the kickstart file:

    The part/partition and autopart commands can't be used at the same time.

fedora-live-python-classroom.ks

@@ -6,3 +6,6 @@
 
 %include fedora-live-workstation.ks
 %include fedora-python-classroom-gnome-common.ks
+
+# https://bugzilla.redhat.com/show_bug.cgi?id=1695796
+part / --size 8192

fedora-python-classroom-gnome-common.ks

@@ -6,9 +6,6 @@
 
 %include fedora-python-classroom-common.ks
 
-# https://bugzilla.redhat.com/show_bug.cgi?id=1695796
-part / --size 8192
-
 %packages
 emacs
 python3-matplotlib-tk