Fix incorrect usage of once flag in async Sentinel (#2718)

In the execute_command of the async Sentinel, the once flag was being
used incorrectly, with its meaning inverted. To fix we just needed to invert
the if and else bodies. This isn't being caught by the tests currently
because the tests of commands that use this flag do not check their
results/effects (for example the "test_ckquorum" test).

CHANGES

@@ -1,3 +1,4 @@
+    * Fix incorrect usage of once flag in async Sentinel
     * asyncio: Fix memory leak caused by hiredis (#2693)
     * Allow data to drain from async PythonParser when reading during a disconnect()
     * Use asyncio.timeout() instead of async_timeout.timeout() for python >= 3.11 (#2602)

redis/asyncio/sentinel.py

@@ -220,13 +220,13 @@ async def execute_command(self, *args, **kwargs):
             kwargs.pop("once")
 
         if once:
+            await random.choice(self.sentinels).execute_command(*args, **kwargs)
+        else:
             tasks = [
                 asyncio.Task(sentinel.execute_command(*args, **kwargs))
                 for sentinel in self.sentinels
             ]
             await asyncio.gather(*tasks)
-        else:
-            await random.choice(self.sentinels).execute_command(*args, **kwargs)
         return True
 
     def __repr__(self):