Upgrade ethers to v6 in wallet (#2747)

* migrate to uint8arrays

* add 0x prefix

* Remaining fixes and cleanup

* Remove duplicate helpers

* slice to subarray

* wallet: fix browser tests

* Address feedback

* Address feedback

* partial migration to tape

* WIP changes

* Finish migrating tests

* revert error message checking in test

* update tests again

* fix test

* test fixes

* upgrade ethers to v6

* Fix tests

* Remove obsolete test

* lint

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Co-authored-by: Jochem Brouwer <jochembrouwer96@gmail.com>