Rococo<>Wococo bridge is replaced by Rococo<Westend bridge, so this PR
removes unneeded code.

- [x] update bridges subtree after
https://github.com/paritytech/parity-bridges-common/pull/2692

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Co-authored-by: command-bot <>
Co-authored-by: Svyatoslav Nikolsky <svyatonik@gmail.com>