[SDK] Fix: Add JSDoc documentation for getSocialIcon function (#5395)

CNCT-2324

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## PR-Codex overview
This PR enhances the documentation for the `getSocialIcon` function, providing a detailed JSDoc comment that explains its purpose, parameters, return value, and includes usage examples.

### Detailed summary
- Added a JSDoc comment for the `getSocialIcon` function.
- Described the function's purpose, parameters, return value, and provided usage examples.
- Changed the return type of `getSocialIcon` to explicitly specify it returns a `string`.

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Author: gregfromstl

packages/thirdweb/src/react/core/utils/walletIcon.ts

@@ -50,8 +50,17 @@ export const socialIcons = {
   github: githubIconUri,
 };
 
-// TODO: this should return actual <svg> elements so they can be themed
-export function getSocialIcon(provider: AuthOption | ({} & string)) {
+/**
+ * Gets the icon URI for a given social authentication provider
+ * @param provider - The authentication provider to get the icon for
+ * @returns A data URI containing the SVG icon for the provider, or a generic wallet icon if the provider is not recognized
+ * @example
+ * ```tsx
+ * const googleIcon = getSocialIcon("google")
+ * const appleIcon = getSocialIcon("apple")
+ * ```
+ */
+export function getSocialIcon(provider: AuthOption | ({} & string)): string {
   switch (provider) {
     case "google":
       return googleIconUri;