Remove 'no cache' directive for POST requests

The response for POST request is only cachable under a specific condition and
qbt doesn't use it.
https://developer.mozilla.org/en-US/docs/Glossary/Cacheable

src/webui/www/private/views/log.html

@@ -361,8 +361,8 @@
 
             new Request.JSON({
                 url: url,
-                noCache: true,
                 method: 'get',
+                noCache: true,
                 onFailure: function(response) {
                     const errorDiv = $('error_div');
                     if (errorDiv)