refactor: improve get_clients_from_cmd_args

[sys9kdr]

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improve the get_clients_from_cmd_args for better readability and consistency.

• Replaced dictionary-based storage with a table for clients in the get_clients_from_cmd_args function.
• Utilized the '#' operator to accurately count clients and enhance code readability.
• Updated the condition for checking if the result table is empty using the '#' operator.

[sys9kdr]

Probably works, but not thoroughly tested yet

[sys9kdr]

Manually, I confirmed that LspRestart and LspStop work.