Fix styling of SharedSecretWrapper.vue if secret is correct

aleksis/apps/maka/frontend/components/shared_secret/SharedSecretWrapper.vue

 <template>
   <v-card
     :flat="sharedSecretStatus || $apollo.queries.sharedSecretStatus.loading"
-    style="width: max-content"
+    :style="{ width: sharedSecretStatus ? '100%' : 'max-content' }"
     class="mx-auto"
   >
     <slot v-if="sharedSecretStatus && !initial" />