UI: added additional check for string and empty string in value card widget

ui-ngx/src/app/modules/home/components/widget/lib/cards/value-card-widget.component.ts

@@ -27,7 +27,7 @@ import {
   ViewChild
 } from '@angular/core';
 import { WidgetContext } from '@home/models/widget-component.models';
-import { formatValue, isDefinedAndNotNull } from '@core/utils';
+import { formatValue, isDefinedAndNotNull, isNotEmptyStr, isString } from '@core/utils';
 import {
   backgroundStyle,
   ColorProcessor,
@@ -183,7 +183,10 @@ export class ValueCardWidgetComponent implements OnInit, AfterViewInit, OnDestro
     const tsValue = getSingleTsValue(this.ctx.data);
     let ts;
     let value;
-    if (tsValue && isDefinedAndNotNull(tsValue[1])) {
+    if (
+      tsValue && isDefinedAndNotNull(tsValue[1]) &&
+      (!isString(tsValue[1]) || isNotEmptyStr(tsValue[1]))
+    ) {
       ts = tsValue[0];
       value = tsValue[1];
       this.valueText = formatValue(value, this.decimals, this.units, false);