The code was wrong and didn't work on systems with OpenSSL compiled without `ripemd160` (which is now the case for the OpenSSL 3.0 default build), because the `try except` clauses were not properly nested.
It should have been:
```
try:
...
except ValueError:
try:
...
except ImportError:
...
```
The last fallback option, which is a slow pure-python implementation (slowdown very noticeable in wallets with many addresses), is no longer really needed as we just made `pycryptodomex` an official dependency.
Note that we also have a (better maintained) ripemd pure-python implementation in the node's test framework, so this also deduplicates code in the monorepo.
Depends on D14132