Do not break dashboard settings UI when time intervals end with trailing comma (#26126)

public/app/features/dashboard/components/DashboardSettings/SettingsCtrl.ts

@@ -255,7 +255,7 @@ export class SettingsCtrl {
   };
 
   onRefreshIntervalChange = (intervals: string[]) => {
-    this.dashboard.timepicker.refresh_intervals = intervals;
+    this.dashboard.timepicker.refresh_intervals = intervals.filter(i => i.trim() !== '');
   };
 
   onNowDelayChange = (nowDelay: string) => {

public/app/features/dashboard/components/DashboardSettings/TimePickerSettings.tsx

@@ -112,7 +112,7 @@ export class TimePickerSettings extends PureComponent<Props, State> {
 
           <div className="gf-form">
             <span className="gf-form-label width-7">Auto-refresh</span>
-            <Input width={60} value={this.getRefreshIntervals()} onChange={this.onRefreshIntervalChange} />
+            <Input width={60} defaultValue={this.getRefreshIntervals()} onBlur={this.onRefreshIntervalChange} />
           </div>
           <div className="gf-form">
             <span className="gf-form-label width-7">Now delay now-</span>