refactor: use Span in random.*

src/wallet/test/wallet_crypto_tests.cpp

@@ -81,7 +81,7 @@ BOOST_AUTO_TEST_CASE(passphrase) {
 
     std::string hash(GetRandHash().ToString());
     std::vector<unsigned char> vchSalt(8);
-    GetRandBytes(vchSalt.data(), vchSalt.size());
+    GetRandBytes(vchSalt);
     uint32_t rounds = InsecureRand32();
     if (rounds > 30000)
         rounds = 30000;