Refactor StatItem to use required color prop without defaults

Replaced optional `color` prop with a required one and removed default value handling. Simplified template binding by directly applying inline styles for color. This improves clarity and ensures consistent color usage.

frontend/src/components/MainNav/BuildStats/StatItem.vue

@@ -1,18 +1,13 @@
 <template>
-  <v-list-item :color="color" :title="title">
+  <v-list-item :style="{ color }" :title="title">
     {{ count }}
   </v-list-item>
 </template>
 
 <script lang="ts" setup>
-const props = defineProps<{
+defineProps<{
   title: string
   count: number
-  color?: string
+  color: string
 }>()
-
-// Provide default values for props
-const { color = 'primary' } = withDefaults(props, {
-  color: 'primary'
-})
 </script>