Custom algorithm added to Registry with a JWA-standard id DON'T replace standard algorithm implementation.

[amryadam]

Describe the bug
Custom algorithm instance added to NestedCollection<SecureDigestAlgorithm<?, ?>with a JWA-standard id DON'T replace (override) the JJWT standard algorithm implementation.

To Reproduce
Steps to reproduce the behavior:
version 0.12.5 , until version 0.12.4 not present

MacAlgorithm customMacAlgorithm;

   try {
            int minKeyBitLength = 100;
            String id = "HS512";
            String jcaName = "HmacSHA512";
            Class<?> c = Class.forName("io.jsonwebtoken.impl.security.DefaultMacAlgorithm");
            Constructor<?> ctor = c.getDeclaredConstructor(String.class, String.class, int.class);
            ctor.setAccessible(true);
            customMacAlgorithm =  (MacAlgorithm) ctor.newInstance(id, jcaName, minKeyBitLength);
        } catch (ClassNotFoundException
                | NoSuchMethodException
                | InstantiationException
                | IllegalAccessException
                | InvocationTargetException e){
            throw new RuntimeException(e);
        }
        try {
			byte[] s = SECRET_BYTE ;
			var key = new SecretKeySpec(s, "HmacSHA512");
			Claims claims = Jwts.parser()
					.verifyWith(key)
					.sig().add(customMacAlgorithm).and().build()
					.parseSignedClaims(token)
					.getPayload();
			return claims;
		} catch (Exception e) {}

2. set break point as screenshot in class io.jsonwebtoken.impl.DefaultJwtParser

Expected behavior
minKeyBitLength should be 100

Screenshots

[lhazlewood]

I'll have to do some deep digging into this since I'm certain we have test cases for overrides, so I don't know why this is happening. We're traveling this week, so we'll be able to look into it next week. Thanks for the issue!