Simplify command ACK

For the time being, YAGNI, and recognize that we never do anything different;
we *always* ACK the message, regardless of the processing outcome.  No need to
worry about "proper handling" later, if it's already done.

compute_endpoint/globus_compute_endpoint/endpoint/endpoint_manager.py

@@ -415,8 +415,8 @@ def _event_loop(self):
                 self.wait_for_children()
 
             try:
-                _command = self._command_queue.get(timeout=1.0)
-                d_tag, props, body = _command
+                d_tag, props, body = self._command_queue.get(timeout=1.0)
+                self._command.ack(d_tag)
                 if props.headers and props.headers.get("debug", False):
                     body_log_b = _redact_url_creds(body, redact_user=False)
                     log.warning(
@@ -448,7 +448,6 @@ def _event_loop(self):
                     f"Unable to deserialize Globus Compute services command."
                     f"  ({e.__class__.__name__}) {e}"
                 )
-                self._command.ack(d_tag)
                 continue
 
             now = round(time.time())
@@ -461,15 +460,13 @@ def _event_loop(self):
                     f"\n  Command timestamp:  {server_cmd_ts:,} ({server_pp_ts})"
                     f"\n  Endpoint timestamp: {now:,} ({endp_pp_ts})"
                 )
-                self._command.ack(d_tag)
                 continue
 
             try:
                 effective_identity = msg["globus_effective_identity"]
                 identity_set = msg["globus_identity_set"]
             except Exception as e:
                 log.error(f"Invalid server command.  ({e.__class__.__name__}) {e}")
-                self._command.ack(d_tag)
                 continue
 
             identity_for_log = (
@@ -485,13 +482,11 @@ def _event_loop(self):
                     "Identity failed to map to a local user name."
                     f"  ({e.__class__.__name__}) {e}{identity_for_log}"
                 )
-                self._command.ack(d_tag)
                 continue
             except Exception as e:
                 msg = "Unhandled error attempting to map user."
                 log.debug(f"{msg}{identity_for_log}", exc_info=e)
                 log.error(f"{msg}  ({e.__class__.__name__}) {e}{identity_for_log}")
-                self._command.ack(d_tag)
                 continue
 
             try:
@@ -503,7 +498,6 @@ def _event_loop(self):
                     "  Identity mapped to a local user name, but local user does not"
                     f" exist.\n  Local user name: {local_username}{identity_for_log}"
                 )
-                self._command.ack(d_tag)
                 continue
 
             try:
@@ -528,8 +522,6 @@ def _event_loop(self):
                     f"    args: {command_args}\n"
                     f"  kwargs: {command_kwargs}{identity_for_log}"
                 )
-            finally:
-                self._command.ack(d_tag)
 
     def cmd_start_endpoint(
         self,