fix(prosody): av_moderation_component default val

resources/prosody-plugins/mod_av_moderation.lua

-local avmoderation_component = module:get_option_string('av_moderation_component', 'avmoderation'..module.host);
+local avmoderation_component = module:get_option_string('av_moderation_component', 'avmoderation.'..module.host);
 
 -- Advertise AV Moderation so client can pick up the address and use it
 module:add_identity('component', 'av_moderation', avmoderation_component);