fix(knowledge): fix type error in connectors-section useCredentialRefreshTriggers call

Same string narrowing fix as add-connector-modal — pass empty string
fallback for providerId.

Author: waleedlatif1

apps/sim/app/workspace/[workspaceId]/knowledge/[id]/components/connectors-section/connectors-section.tsx

@@ -334,7 +334,7 @@ function ConnectorCard({
     workspaceId,
   })
 
-  useCredentialRefreshTriggers(refetchCredentials, providerId, workspaceId)
+  useCredentialRefreshTriggers(refetchCredentials, providerId ?? '', workspaceId)
 
   const missingScopes = useMemo(() => {
     if (!credentials || !connector.credentialId) return []