KIP-393 — Time windowed serde to properly deserialize changelog input topic

Accepted Kafka 2.2 Streams

Fixes `TimeWindowedDeserializer` to correctly decode windowed keys read from Streams changelog topics by accounting for the sequence number appended by `WindowKeySchema` during serialization. The existing `TimeWindowedSerde` uses `WindowKeySchema.fromStoreKey()` which does not strip the sequence number, producing incorrect window timestamps when a Streams application reads back its own changelog.

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