feat: Don't hide thumbnail on hover (#10935)

### Old behavior


https://github.com/user-attachments/assets/5d7524c1-b1ca-454f-8e89-843ca25d017e

### New behavior


https://github.com/user-attachments/assets/49814190-d6b4-4553-bced-3987be3583e2

---------

Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>

app/javascript/dashboard/components/widgets/Thumbnail.vue

@@ -156,13 +156,14 @@ export default {
     </slot>
     <img
       v-if="badgeSrc"
-      class="source-badge"
+      class="source-badge z-20"
       :style="badgeStyle"
       :src="`/integrations/channels/badges/${badgeSrc}.png`"
       alt="Badge"
     />
     <div
       v-if="showStatusIndicator"
+      class="z-20"
       :class="`source-badge user-online-status user-online-status--${status}`"
       :style="statusStyle"
     />