fix(AuthForm): ensure header is shown with leading slot (#5405)

Co-authored-by: Benjamin Canac <canacb1@gmail.com>

Author: rodriciru

src/runtime/components/AuthForm.vue

@@ -187,7 +187,7 @@ defineExpose({
 
 <template>
   <Primitive :as="as" :class="ui.root({ class: [props.ui?.root, props.class] })">
-    <div v-if="(icon || !!slots.icon) || (title || !!slots.title) || (description || !!slots.description) || !!slots.header" :class="ui.header({ class: props.ui?.header })">
+    <div v-if="(icon || !!slots.leading) || (title || !!slots.title) || (description || !!slots.description) || !!slots.header" :class="ui.header({ class: props.ui?.header })">
       <slot name="header">
         <div v-if="icon || !!slots.leading" :class="ui.leading({ class: props.ui?.leading })">
           <slot name="leading" :ui="ui">

test/components/__snapshots__/AuthForm-vue.spec.ts.snap

@@ -428,7 +428,11 @@ exports[`AuthForm > renders with icon correctly 1`] = `
 
 exports[`AuthForm > renders with leading slot correctly 1`] = `
 "<div class="w-full space-y-6">
-  <!--v-if-->
+  <div class="flex flex-col text-center">
+    <div class="mb-2">Leading</div>
+    <!--v-if-->
+    <!--v-if-->
+  </div>
   <div class="gap-y-6 flex flex-col">
     <!--v-if-->
     <!--v-if-->

test/components/__snapshots__/AuthForm.spec.ts.snap

@@ -446,7 +446,11 @@ exports[`AuthForm > renders with icon correctly 1`] = `
 
 exports[`AuthForm > renders with leading slot correctly 1`] = `
 "<div class="w-full space-y-6">
-  <!--v-if-->
+  <div class="flex flex-col text-center">
+    <div class="mb-2">Leading</div>
+    <!--v-if-->
+    <!--v-if-->
+  </div>
   <div class="gap-y-6 flex flex-col">
     <!--v-if-->
     <!--v-if-->