As reported by Michael Seyfried in a blog comment:
Currently the com.liferay.faces.portal-4.1.0.jar is not compatible with Liferay CE 7.3.6 GA7 because it imports com.liferay.wiki.engine with version="[1.2,2)". The com.liferay.wiki.engine version has been upgraded in Liferay CE 7.3.6 GA7 to version 2.0.0. To use com.liferay.faces.portal-4.1.0.jar in Liferay CE 7.3.6 GA7 it will be necessary to modify it. To work around this issue I modified the import to version="[1.2,3.0.0)"