Update src/client/sse.ts

nullish coalescing operator ?? instead of the logical OR operator || to handle the case where this?._eventSourceInit?.fetch or this._fetch might be null or undefined but not falsy

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: cliffhall

src/client/sse.ts

@@ -251,7 +251,7 @@ const fetchImpl = (this?._eventSourceInit?.fetch ?? this._fetch ?? fetch) as typ
         signal: this._abortController?.signal,
       };
 
-      const response = await (this._fetch ?? fetch)(this._endpoint, init);
+const response = await (this._fetch ?? fetch)(this._endpoint, init);
       if (!response.ok) {
         if (response.status === 401 && this._authProvider) {