fix: fix race condition with docs voting feature (#256)

This fixes a race condition that could occasionally cause the page to
show an error if the rendering of the page completed before the request
to the voting backend API completed. This fixes this race condition by
providing stubbed / initial values in the voting context instead of
`undefined`.

The error that was occasionally reproducible": 
<img width="948" alt="image"
src="https://github.com/user-attachments/assets/1ba87db6-2aad-4879-b153-2d8dd6f3743a">

website/context/VotingContext.tsx

@@ -37,7 +37,16 @@ interface VotingContextProps {
   getVoteCount: (feature: string) => number;
 }
 
-const VotingContext = createContext<VotingContextProps | undefined>(undefined);
+const VotingContext = createContext<VotingContextProps>({
+  localStorageVotes: [],
+  features: [],
+  upvote: async () => {},
+  downvote: async () => {},
+  getVoteStatus: () => "none",
+  isUpvoted: () => false,
+  isDownvoted: () => false,
+  getVoteCount: () => 0,
+});
 
 const doApiRequest = async (
   method: "GET" | "POST",