I found out during the cleanup of this deprecation message in the
`polkadot-fellows` repository that we deprecated `CurrencyAdapter`
without making the recommended changes.


## TODO
- [ ] fix `polkadot-fellows` bump to 1.6.0
https://github.com/polkadot-fellows/runtimes/pull/159

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Co-authored-by: Francisco Aguirre <franciscoaguirreperez@gmail.com>