ui: remove white backgrounds from package versions and system report

removes the style that gets added directly to the element of the
package versions and system report views. this makes them harder to
style through css as normal selectors cannot override the element's
style. since they behave properly without these styles anyway, remove
them.

Signed-off-by: Stefan Sterz <s.sterz@proxmox.com>

www/ServerStatus.js

@@ -60,7 +60,6 @@ Ext.define('PBS.ServerStatus', {
 	    id: 'pkgversions',
 	    padding: 5,
 	    style: {
-		'background-color': 'white',
 		'white-space': 'pre',
 		'font-family': 'monospace',
 	    },

www/Subscription.js

@@ -42,7 +42,6 @@ Ext.define('PBS.Subscription', {
 	    itemId: 'system-report-view',
 	    scrollable: true,
 	    style: {
-		'background-color': 'white',
 		'white-space': 'pre',
 		'font-family': 'monospace',
 		padding: '5px',