FLINK-31361 - Added the right shaded dependency for SQL client connector for kafka - Updated kafka.md

[diptimanr]

Modified the documentation on using the right dependency for 'properties.sasl.jaas.config'. When using 'flink-sql-connector-kafka.jar', existing document doesn't use the shaded dependency. Also added the name of the jar file (flink-sql-connector-kafka-x.xx.x.jar).

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