Infinite image requests in vertical demo

[matsbryntse]

http://lh/bryntum-suite/scheduler/examples/vertical/

Set
resourceImagePath : './',

```

/* eslint-disable no-unused-vars */
import '../_shared/shared.js'; // not required, our example styling etc.
import '../../lib/Scheduler/feature/TimeRanges.js';
import '../../lib/Scheduler/feature/ResourceTimeRanges.js';
import Scheduler from '../../lib/Scheduler/view/Scheduler.js';
import WidgetHelper from '../../lib/Core/helper/WidgetHelper.js';
import DateHelper from '../../lib/Core/helper/DateHelper.js';

let scheduler;

scheduler = new Scheduler({
adopt : 'container',
minHeight : '20em',

mode : 'vertical',

crudManager : {
    autoLoad  : true,
    transport : {
        load : {
            url : 'data/data.json'
        }
    }
},

startDate      : new Date(2019, 11, 23),
endDate        : new Date(2019, 11, 28),
viewPreset : 'dayAndWeek',
barMargin      : 5,
resourceMargin : 5,
eventStyle     : 'colored',
tickSize       : 140,
resourceImagePath : './',

features : {
    timeRanges : {
        enableResizing      : true,
        showCurrentTimeLine : true
    },
    resourceTimeRanges : true
},

resourceColumns : {
    columnWidth : 300
    //headerRenderer : ({ resourceRecord }) => `${resourceRecord.id} - ${resourceRecord.name}`
},

eventRenderer : ({ eventRecord }) => `
    <div class="time">${DateHelper.format(eventRecord.startDate, 'LT')}</div>
    <div class="name">${eventRecord.name}</div>
`

});