[Mobile] Add line break between header options (#918)

Fixes an issue where "Time Period" shows up on a separate
line from its dropdown

app/templates/header.html

@@ -136,6 +136,7 @@
                 </option>
             {% endfor %}
         </select>
+        <br />
         <label for="config-time-period">{{ translation['config-time-period'] }}: </label>
         <select name="tbs" id="result-time-period">
             {% for time_period in time_periods %}