Fix Python3.13 compatibility regarding urllib.parse module

Python 3.13 fixed handling relative paths in urllib.parse module.
Specifically, relative file URL is now constructed as file:path instead
of converting it to absolute file:///path. This breaks
salt.utils.url.create which expects file:/// specifically. The mismatch
results in for example changing salt://top.sls into salt://.sls and thus
not finding the top file.

Fix this by handling both prefixes.

Relevant python change: python/cpython#85110
Fixes: saltstack#66898

Author: marmarek

changelog/66898.fixed.md

@@ -0,0 +1 @@
+Fixed Python 3.13 compatibility regarding urllib.parse module

salt/utils/url.py

@@ -4,7 +4,7 @@
 
 import re
 import sys
-from urllib.parse import urlparse, urlunparse
+from urllib.parse import urlparse, urlunparse, urlunsplit
 
 import salt.utils.data
 import salt.utils.path
@@ -46,8 +46,7 @@ def create(path, saltenv=None):
     path = salt.utils.data.decode(path)
 
     query = f"saltenv={saltenv}" if saltenv else ""
-    url = salt.utils.data.decode(urlunparse(("file", "", path, "", query, "")))
-    return "salt://{}".format(url[len("file:///") :])
+    return f'salt://{salt.utils.data.decode(urlunsplit(("", "", path, query, "")))}'
 
 
 def is_escaped(url):