add back multipart provider

distribution/feature-packs/server-feature-pack/src/main/resources/modules/system/layers/keycloak/org/keycloak/keycloak-services/main/module.xml

@@ -49,6 +49,7 @@
         <module name="javax.mail.api"/>
         <module name="javax.xml.soap.api"/>
         <module name="org.jboss.resteasy.resteasy-jaxrs"/>
+        <module name="org.jboss.resteasy.resteasy-multipart-provider"/>
         <module name="org.jboss.dmr"/>
         <module name="javax.servlet.api"/>
         <module name="com.fasterxml.jackson.core.jackson-core"/>