title: Close shinyWidgets dropdownButton by clicking a button
body: <p>Is there a way to close the context menu of a <code>dropdownButton</code> in a shiny app after clicking on a button? I was looking for an attribute like <code>closed</code>/<code>opened</code> in the <code>dropdownButton</code>-documentation and couldn't find anything but I believe there must be a way to do this.</p>
  
  <p>This is an example app:</p>
  
  <pre><code>library(shiny)
  library(shinyWidgets)
  
  ui &lt;- fluidPage(
    dropdownButton(
      actionButton("button", "Press this Button to close the dropdownButton!"),
      circle = TRUE, status = "primary", icon = icon("user-circle")
    )
  )
  
  server &lt;- function(input, output) {
    observeEvent(
      input$button, {
        # Set dropdownButton closed
        print("Test")
      }
    )
  
  }
  
  shinyApp(ui = ui, server = server)
  </code></pre>