Python: Bug: Python Sequential Planner config.json execution_settings "stop_sequences" should be "stop"

[AndreasKunar]

Describe the bug
In file python/semantic_kernel/planners/sequential_planner/Plugins/SequentialPlanning/config.json, the item "stop_sequences" in "execution_settings" should be named "stop" instead, since OpenAIPromptExecutionSettings and others just define this setting as simply "stop". There is no "stop_sequences" setting in any of the Python ai service's' PromptExecutionSettings.

Additional context
Very low priority. There currently seems no execution impact from this, but it's still a bug.