oh-canvas: Fix exception on empty initial svg config (#2864)

This fixes a nasty bug on initial setup of an embedded SVG that has no configuration yet.

---------

Also-by: Florian Hotze <dev@florianhotze.com>
Signed-off-by: Stefan Höhn <mail@stefanhoehn.com>

bundles/org.openhab.ui/web/src/components/widgets/layout/oh-canvas-embedded-svg-mixin.js

@@ -76,6 +76,8 @@ export default {
      * Remember to unsubscribe from the mutations using {@link unsubscribeEmbeddedSvgStateTracking} when the component is destroyed.
      */
     setupEmbeddedSvgStateTracking () {
+      if (!this.config.embeddedSvgActions) return
+
       const svg = this.$refs.canvasBackground.querySelector('svg')
       const subElements = svg.querySelectorAll('[openhab]')
 
@@ -146,7 +148,7 @@ export default {
       if (this.context.editmode || (!this.context.editmode && this.config.embedSvgFlashing)) {
         const tagName = el.tagName
         // fill green if item config is available, red if config is still missing
-        const fillColor = (this.config.embeddedSvgActions[el.id]) ? 'rgb(0, 255, 0)' : 'rgb(255, 0, 0)'
+        const fillColor = (this.config.embeddedSvgActions && this.config.embeddedSvgActions[el.id]) ? 'rgb(0, 255, 0)' : 'rgb(255, 0, 0)'
         if (tagName !== 'g' && !el.flashing) {
           // sometimes instead of fill, stroke colors are used, so if fill = none, then we use stroke instead
           const attributeName = (el.style.fill !== 'none') ? 'fill' : 'stroke'
@@ -190,7 +192,9 @@ export default {
       if (this.context.editmode) {
         this.openSvgSettingsPopup(el.id)
       } else {
-        this.performAction(null, null, this.config.embeddedSvgActions[el.id], this.context)
+        if (this.config.embeddedSvgActions && this.config.embeddedSvgActions[el.id]) {
+          this.performAction(null, null, this.config.embeddedSvgActions[el.id], this.context)
+        }
       }
     },
     /**