GSettings - run data model transations while setting up

This makes sure all schema changes are in effect before
the first consumer can query them. For example this will
prevent a one-time re-occurrence of the tip of the day dialog
the first time the new migrations are run.

gnucash/gnucash.cpp

@@ -145,9 +145,6 @@ scm_run_gnucash (void *data, [[maybe_unused]] int argc, [[maybe_unused]] char **
     scm_set_current_module(main_mod);
     scm_c_use_module("gnucash app-utils");
 
-    /* Check whether the settings need a version update */
-    gnc_gsettings_version_upgrade ();
-
     gnc_gnome_utils_init();
     gnc_search_core_initialize ();
     gnc_hook_add_dangler(HOOK_UI_SHUTDOWN, (GFunc)gnc_search_core_finalize, NULL, NULL);

libgnucash/app-utils/gnc-gsettings.cpp

@@ -627,6 +627,10 @@ void gnc_gsettings_load_backend (void)
     prefsbackend->block_all = gnc_gsettings_block_all;
     prefsbackend->unblock_all = gnc_gsettings_unblock_all;
 
+    /* Run any data model changes for the backend before it's used
+     * by anyone */
+    gnc_gsettings_version_upgrade();
+
     LEAVE("Prefsbackend bind = %p", prefsbackend->bind);
 }