fix: Revert "refactor: remove default where a prop is required"

This reverts commit 74f8adb for
NcRichContenteditable to prevent behavior changes.

Author: susnux

src/components/NcRichContenteditable/NcRichContenteditable.vue

@@ -332,11 +332,12 @@ export default {
 		},
 
 		/**
-		 * The content
+		 * The text content.
+		 * This might become required in the next future and should always be set!
 		 */
 		modelValue: {
 			type: String,
-			required: true,
+			default: '',
 		},
 
 		/**