Move relationship item spacing class to parent

This prevents an `.mb-1` on the last child, which prevents single item UIs from aligning center when using flex box (e.g. link fieldtype).

Author: jackmcdade

resources/js/components/inputs/relationship/Item.vue

@@ -1,7 +1,7 @@
 <template>
 
     <div
-        class="item mb-1 select-none"
+        class="item select-none"
         :class="{ 'invalid': item.invalid }"
     >
         <div class="item-move" v-if="sortable">&nbsp;</div>

resources/js/components/inputs/relationship/RelationshipInput.vue

@@ -20,7 +20,7 @@
         <loading-graphic v-if="initializing" :inline="true" />
 
         <template v-if="!initializing && !usesSelectField">
-            <div ref="items" class="relationship-input-items outline-none">
+            <div ref="items" class="relationship-input-items space-y-1 outline-none">
                 <component
                     :is="itemComponent"
                     v-for="(item, i) in items"