gh-36894: Adjust the sync label bot to reflect recent GitHub CLI changes
    
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At least since version 2.40.0 of `gh` the output of `gh auth status` has
changed. This broke the method `bot_login` where the bot's login name is
obtained. The first failure appeared on 13.12 in [this scheduled run](ht
tps://github.com/sagemath/sage/actions/runs/7199213174/job/19610401946).
More specifically, the word before the login name used for positioning
has changed from `as` to `account`.


In a logfile it looks like this:

```
Run chmod a+x .github/sync_labels.py
INFO:root:cmdline_args (1) ['https://github.com/sagemath/sage']
INFO:root:url: https://github.com/sagemath/sage
INFO:root:Create label handler for pull request #sage and actor
sagetrac-github-bot
Traceback (most recent call last):
  File "/home/runner/work/sage/sage/.github/sync_labels.py", line 1081,
in <module>
    gh = GhLabelSynchronizer(url, default_actor)
  File "/home/runner/work/sage/sage/.github/sync_labels.py", line 157,
in __init__
    self.bot_login()
  File "/home/runner/work/sage/sage/.github/sync_labels.py", line 244,
in bot_login
    self._bot_login = l[l.index('as')+1]
ValueError: 'as' is not in list
Error: Process completed with exit code 1.
```

This PR does the following:

* implements an adjustment to this change
* avoids raising an error if the bot name cannot be discovered (to
better behave with similar changes in the future)
* adds more log messages to make it easier to identify similar issues



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### ⌛ Dependencies

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URL: #36894
Reported by: Sebastian Oehms
Reviewer(s): Kwankyu Lee

Author: Release Manager

.github/sync_labels.py

@@ -141,6 +141,7 @@ def __init__(self, url, actor):
         self._commits = None
         self._commit_date = None
         self._bot_login = None
+        self._gh_version = None
 
         s = url.split('/')
         self._owner = s[3]
@@ -235,13 +236,30 @@ def bot_login(self):
         """
         if self._bot_login:
             return self._bot_login
-        cmd = 'gh auth status'
         from subprocess import run
+        cmd = 'gh version'
+        capt = run(cmd, shell=True, capture_output=True)
+        self._gh_version = str(capt.stdout).split('\\n')[0]
+        info('version: %s' % self._gh_version)
+        cmd = 'gh auth status'
         capt = run(cmd, shell=True, capture_output=True)
-        l = str(capt.stderr).split()
-        if not 'as' in l:
-            l = str(capt.stdout).split()
-        self._bot_login = l[l.index('as')+1]
+        errtxt = str(capt.stderr)
+        outtxt = str(capt.stdout)
+        debug('auth status err: %s' % errtxt)
+        debug('auth status out: %s' % outtxt)
+        def read_login(txt, position_mark):
+            for t in txt:
+                for p in position_mark:
+                    # the output text has changed from as to account
+                    # around version 2.40.0
+                    l = t.split()
+                    if p in l:
+                        return l[l.index(p)+1]
+        self._bot_login = read_login([errtxt, outtxt], ['account', 'as'])
+        if not self._bot_login:
+            self._bot_login = default_bot
+            warning('Bot is unknown')
+            return self._bot_login
         if self._bot_login.endswith('[bot]'):
             self._bot_login = self._bot_login.split('[bot]')[0]
         info('Bot is %s' % self._bot_login)