Use `HttpExecutionStrategies.difference` in jersey router

[idelpivnitskiy]

We have a modified implementation of HttpExecutionStrategies.difference function in http-router-jersey: https://github.com/apple/servicetalk/blob/464554ad984bc4897e7ba72e54a2ac0f12a9ecd9/servicetalk-http-router-jersey/src/main/java/io/servicetalk/http/router/jersey/EndpointEnhancingRequestFilter.java#L487-L508

We introduced it #682 to improve accuracy according to jersey router specifics. However, we should reconsider this approach and consolidate the difference logic in one place, because there should be no difference between router implementations. See discussion on gRPC router implementation: https://github.com/apple/servicetalk/pull/912#discussion_r364392328