fix: empty duplicate alias warning on page udpate

server/models/pages.mjs

@@ -477,7 +477,7 @@ export class Page extends Model {
         throw new Error('ERR_PAGE_ALIAS_TOO_LONG')
       } else if (!aliasRegex.test(patch.alias)) {
         throw new Error('ERR_PAGE_INVALID_ALIAS')
-      }
+      } else if (patch.alias.length > 0) {
         const dupAliasCheck = await WIKI.db.pages.query().where({
           siteId: ogPage.siteId,
           alias: patch.alias
@@ -486,6 +486,7 @@ export class Page extends Model {
           throw new Error('ERR_PAGE_DUPLICATE_ALIAS')
         }
       }
+    }
 
     if ('content' in opts.patch) {
       patch.content = opts.patch.content