fix: logo and custom branding (#10930)

This PR has the following changes

1. Update `Logo.vue` to fetch the logo from globalConfig and fallback to
SVG if required.
2. Update the default `public/brand-assets/logo_thumbnail.svg` to use
the new colors.

### Preview


https://github.com/user-attachments/assets/505a1d05-cd05-4b86-9fe7-c05334f09b25

![CleanShot 2025-02-19 at 10 56
23@2x](https://github.com/user-attachments/assets/084064b9-5df5-4d11-9b6a-b511c6047001)

app/javascript/dashboard/components-next/icon/Logo.vue

@@ -1,6 +1,21 @@
+<script setup>
+import { useAttrs } from 'vue';
+import { useMapGetter } from 'dashboard/composables/store';
+
+const attrs = useAttrs();
+const globalConfig = useMapGetter('globalConfig/get');
+</script>
+
 <template>
+  <img
+    v-if="globalConfig.logoThumbnail"
+    v-bind="attrs"
+    :src="globalConfig.logoThumbnail"
+  />
   <svg
+    v-else
     v-once
+    v-bind="attrs"
     width="16"
     height="16"
     viewBox="0 0 16 16"