make the code palette optional

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

packages/theme/report.api.md

@@ -81,7 +81,7 @@ export type BackstagePaletteAdditions = {
     closeButtonColor?: string;
     warning?: string;
   };
-  code: {
+  code?: {
     background?: string;
   };
 };

packages/theme/src/base/types.ts

@@ -82,7 +82,7 @@ export type BackstagePaletteAdditions = {
     closeButtonColor?: string;
     warning?: string;
   };
-  code: {
+  code?: {
     background?: string;
   };
 };