which SecurityProvider is EDC using?

[ndr-brt]

While working at this PR: #2369
I had a curious issue: the DefaultPrivateKeyParseFunctionTest started breaking on the CI and from the command line, while it was working running it from the IDE.

After a sleepless night I found out that the problem was with the SecurityProvider, because, adding the EdcHttpClientImplTest suite that, uses mockserver. Apparently, mockserver registers internally the BouncyCastle security provider, and that made the DefaultPrivateKeyParseFunctionTest.verifyParseSuccess fail because with the BC provider the algorithm for an EC key is ECDSA, while for the whatever provider we are using (are we aware of this?) is EC.

So my question is, we are using BouncyCastle pretty extensively for crypto in the whole EDC, could it be reasonable to register and use its security provider?
To add some additional confusion, the registration of the BC security context is also done by FsRsaPrivateKeyResolverTest, otherwise it will fail, but this let understand that at runtime it gets registered somewhere.
At this point, is at runtime the BC security provider registered or not?