Make edit header view available by default in ui (#649)

Without specifying the headers in code, an user cannot change the headers in springwolf-ui

Solution: Always show the header edit box so that an user can add headers manually

springwolf-ui/src/app/components/channels/channel-main/channel-main.component.html

@@ -35,7 +35,7 @@ <h4>Message Binding</h4>
             "
           ></textarea>
         </div>
-        <div [hidden]="!(headersExample?.lineCount > 1)" class="flex-column">
+        <div class="flex-column">
           <h4>Header</h4>
           <textarea
             spellcheck="false"