Describe the bug

If I have a content JWE, and it has no "cty", and the payload content happens to be parseable as JSON, then parseEncryptedContent fails with io.jsonwebtoken.UnsupportedJwtException: Unexpected Claims JWE.

To Reproduce

    Password password = Keys.password("password".toCharArray());
    String jwe = Jwts.builder()
        .content(new byte[] { 0x7B, 0x7D })
        .encryptWith(password, Jwts.KEY.PBES2_HS512_A256KW, Jwts.ENC.A256GCM)
        .compact();
    byte[] payload =  Jwts.parser()
        .decryptWith(password)
        .build()
        .parseEncryptedContent(jwe)
        .getPayload();

This code throws io.jsonwebtoken.UnsupportedJwtException: Unexpected Claims JWE.

Expected behavior

I expect to get the content, which happens to be the two bytes corresponding to the characters '{' and '}'.