WebSession: fix for list of admin activities

• Adds a missing if-statement to tmpl_account_adminactivities() thus fixing the "Configure BibKnowledge" activity link to be bound to the "cfgbibformat" action rather than the "cfgbibknowledge" one. (closes #1444)

Reported-by: Sebastian Witowski <sebastian.witowski@cern.ch>
Reviewed-by: Tibor Simko <tibor.simko@cern.ch>