use SystemRandom for randomshuffle instead of own rolled implementation

src/onionrcrypto/cryptoutils/randomshuffle.py

@@ -1,13 +1,6 @@
-import secrets
+from random import SystemRandom
+
 def random_shuffle(theList):
     myList = list(theList)
-    shuffledList = []
-    myListLength = len(myList) + 1
-    while myListLength > 0:
-        removed = secrets.randbelow(myListLength)
-        try:
-            shuffledList.append(myList.pop(removed))
-        except IndexError:
-            pass
-        myListLength = len(myList)
-    return shuffledList
+    SystemRandom().shuffle(myList)
+    return myList