chore: downgrade @openedx/brand-openedx to ^1.2.3 (#1671)

Reverts the v2 bump from openedx/public-engineering#505 while keeping
the existing @edx/brand npm alias. Refs openedx/public-engineering#508.

Author: arbrandes

package-lock.json

@@ -29,7 +29,7 @@
     "url": "https://github.com/openedx/frontend-app-authn/issues"
   },
   "dependencies": {
-    "@edx/brand": "npm:@openedx/brand-openedx@^2.0.0",
+    "@edx/brand": "npm:@openedx/brand-openedx@^1.2.3",
     "@edx/frontend-platform": "^8.7.0",
     "@edx/openedx-atlas": "^0.6.0",
     "@fortawesome/fontawesome-svg-core": "6.7.2",