ERROR TypeError: Cannot read properties of null (reading 'themePath')

[Murhaf Sousli]

In case highlight.js was imported from outside the plugin loader, we get the error
ERROR TypeError: Cannot read properties of null (reading 'themePath')

Need to check if options is defined

ngx-highlightjs/projects/ngx-highlightjs/src/lib/highlight.loader.ts

Lines 51 to 53 in b4b7ba2

 if (this._options.themePath) { 
   this.loadTheme(this._options.themePath); 
 }