Fix: Correct return type and preserve response timing info (#1773)
The commit introduces the following enhancements:
1. Type Correction for race-network-and-fetch-event: Modified the race-network-and-fetch-event algorithm to
consistently return the correct value type. This addresses a previous inconsistency where the algorithm could
yield a value of a different, incorrect type.
2. Preservation of Response Timing Information: Ensured that timing information within the response, particularly the
fetch event dispatch time, is retained when the fetch event's value is utilized. This resolves an issue where such
timing data was previously being discarded.