feat: Add multiline support for channel greeting message (#2952)

app/javascript/shared/components/GreetingsEditor.vue

@@ -0,0 +1,78 @@
+<template>
+  <section>
+    <label v-if="richtext" class="greetings--richtext">
+      <woot-message-editor
+        v-model="greetingsMessage"
+        :is-format-mode="true"
+        class="input"
+        :placeholder="placeholder"
+        :min-height="4"
+        @input="handleInput"
+      />
+    </label>
+    <resizable-text-area
+      v-else
+      v-model="greetingsMessage"
+      rows="4"
+      type="text"
+      class="medium-9 greetings--textarea"
+      :label="label"
+      :placeholder="placeholder"
+      @input="handleInput"
+    />
+  </section>
+</template>
+
+<script>
+import WootMessageEditor from 'dashboard/components/widgets/WootWriter/Editor';
+import ResizableTextArea from 'shared/components/ResizableTextArea';
+
+export default {
+  components: {
+    WootMessageEditor,
+    ResizableTextArea,
+  },
+  props: {
+    value: {
+      type: String,
+      default: '',
+    },
+    richtext: {
+      type: Boolean,
+      default: false,
+    },
+    label: {
+      type: String,
+      default: '',
+    },
+    placeholder: {
+      type: String,
+      default: '',
+    },
+  },
+  data() {
+    return {
+      greetingsMessage: this.value,
+    };
+  },
+  watch: {
+    value: function (newValue) {
+      this.greetingsMessage = newValue;
+    },
+  },
+  methods: {
+    handleInput() {
+      this.$emit('input', this.greetingsMessage);
+    },
+  },
+};
+</script>
+
+<style scoped>
+.greetings--richtext {
+  padding: 0 var(--space-normal);
+  border-radius: var(--border-radius-normal);
+  border: 1px solid var(--color-border);
+  margin: 0 0 var(--space-normal);
+}
+</style>