[git_auth] Fix YieldConfigRegexp type

It compiles it internally

Bug: b/351071334
Change-Id: I4a1b2b47b9813b3a1e11bbb07b328ffcc50bc609
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5744335
Reviewed-by: Robbie Iannucci <iannucci@chromium.org>
Commit-Queue: Allen Li <ayatane@chromium.org>
Reviewed-by: Yiwei Zhang <yiwzhang@google.com>

git_cl.py

@@ -6890,8 +6890,8 @@ def CMDcheckout(parser, args):
 
     target_issue = str(issue_arg.issue)
 
-    output = scm.GIT.YieldConfigRegexp(
-        settings.GetRoot(), re.compile(r'branch\..*\.' + ISSUE_CONFIG_KEY))
+    output = scm.GIT.YieldConfigRegexp(settings.GetRoot(),
+                                       r'branch\..*\.' + ISSUE_CONFIG_KEY)
 
     branches = []
     for key, issue in output: