Fix race condition in color calculation.

src/components/user_card_content/user_card_content.vue

@@ -61,11 +61,14 @@
     props: [ 'user' ],
     computed: {
       headingStyle () {
+        let color = this.$store.state.config.colors['base00']
+        if (color) {
           let rgb = this.$store.state.config.colors['base00'].match(/\d+/g)
           return {
             backgroundColor: `rgb(${Math.floor(rgb[0] * 0.53)}, ${Math.floor(rgb[1] * 0.56)}, ${Math.floor(rgb[2] * 0.59)})`,
             backgroundImage: `url(${this.user.cover_photo})`
           }
+        }
       },
       bodyStyle () {
         return {