Merge pull request #14590 from ClickHouse/remove-useless-lc-code

Remove useless line.

src/Columns/ColumnLowCardinality.h

@@ -170,7 +170,6 @@ public:
     size_t sizeOfValueIfFixed() const override { return getDictionary().sizeOfValueIfFixed(); }
     bool isNumeric() const override { return getDictionary().isNumeric(); }
     bool lowCardinality() const override { return true; }
-    bool isNullable() const override { return isColumnNullable(*dictionary.getColumnUniquePtr()); }
 
     const IColumnUnique & getDictionary() const { return dictionary.getColumnUnique(); }
     const ColumnPtr & getDictionaryPtr() const { return dictionary.getColumnUniquePtr(); }