shiny demo: don't try to use access token

Change-Id: Iaf8e923a6377068aa52729e9c408aea6ffea2744
diff --git a/inst/shiny-apps/frequency_curves/server.R b/inst/shiny-apps/frequency_curves/server.R
index 26125cc..a2e1477 100644
--- a/inst/shiny-apps/frequency_curves/server.R
+++ b/inst/shiny-apps/frequency_curves/server.R
@@ -3,7 +3,7 @@
 } else {
   hc_theme_hcrt()
 }
-rsr <- new("KorAPConnection", verbose = TRUE)
+rsr <- new("KorAPConnection", verbose = TRUE, accessToken = NULL)
 vc <- "(textType = /Zeit.*/ | textTypeRef=Plenarprotokoll) & availability!=QAO-NC-LOC:ids & creationDate in"
 years <- c(2005:2020)
 from <- 2005