add missing size prop to symbol type in victory-legend (#2523)

Co-authored-by: Charlie Brown <carbonrobot@gmail.com>

Author: alisongs

.changeset/warm-rocks-rest.md

@@ -0,0 +1,5 @@
+---
+"victory-legend": patch
+---
+
+Add missing size property to TS definitions

packages/victory-legend/src/index.d.ts

@@ -31,6 +31,7 @@ export interface VictoryLegendProps
     };
     symbol?: {
       fill?: string;
+      size?: number;
       type?: string;
     };
   }>;