Fix OAuth code exchange and go lint

Authorization-code exchange used ExternalClientID, which
is empty for registered clients and broke e2e token
grants. Pass the authenticated client's GID instead.

Also satisfy wsl_v5 blank-line rules, wire the delete
reference dialog through its mutation hook, and name the
filemanager logger.

Signed-off-by: Bryan Frimin <bryan@probo.com>

pkg/server/api/connect/v1/oauth2_handler.go

@@ -466,7 +466,7 @@ func (h *OAuth2Handler) handleAuthorizationCodeGrant(w http.ResponseWriter, r *h
 
 	result, err := h.iam.OAuth2ServerService.ExchangeAuthorizationCode(
 		r.Context(),
-		client.ExternalClientID,
+		client.ID.String(),
 		in.Code,
 		in.RedirectURI,
 		in.CodeVerifier,