KeyManagerImpl always taking the first client alias

In `KeyManagerImpl` the logic that chooses a client alias in method `chooseClientAlias` always takes the first client alias. For my use case, I am using the `KeyManagerImpl` for MTLS communication to the backend.

My scenario is that I have 2 keypairs in my KeymManager keystore. One of the keypair's certificate is about to be expired, so i created a new keypair and both of these keypairs are signed by the same CA, thus when talking to my backend the same Principal Names are return when `chooseClientAlias` is invoked.

Now the problem comes when the backend removes the expired leaf certificate, but `chooseClientAlias` still will choose the keypair with the expired certificate and an http 403 will occur despite my keystore having both the expired and the non-expired keypairs.

this happens because of the below
```
@Override
public String chooseClientAlias(String[] keyTypes, Principal[] issuers, Socket socket) {
final String[] al = chooseAlias(keyTypes, issuers);
return (al == null ? null : al[0]);
}
```
Conscrypt `KeyManagerImpl` will just take the first alias no matter what. Can there be some form of deterministic behaviour where the array of aliases be sorted first b4 returning like below? By doing this i can somehow decide which keypair is used first when creating the keystore.

```
@Override
public String chooseClientAlias(String[] keyTypes, Principal[] issuers, Socket socket) {
final String[] al = chooseAlias(keyTypes, issuers);
if (al == null) return null;
Arrays.sort(al);
return al[0];
}
```