use ternary conditional instead if

lib/src/models/rules/insert.dart

@@ -568,8 +568,7 @@ class PreserveInlineStylesRule extends InsertRule {
       if (prevData.endsWith('\n')) {
         /// If current line is empty get attributes from a prior line
         final currLine = itr.next();
-        if (currLine.data is String) {
+        final currData = currLine.data is String ? currLine.data as String : null;
-          final currData = currLine.data as String?;
         if (currData != null && (currData.isEmpty || currData[0] == '\n')) {
           if (prevData.trimRight().isEmpty) {
             final back =
@@ -583,7 +582,6 @@ class PreserveInlineStylesRule extends InsertRule {
         }
       }
     }
-    }
 
     final attributes = <String, dynamic>{};
     if (prev.attributes != null) {