Fix #1741, Remove SB get last message sender info requirement

docs/cFE_FunctionalRequirements.csv

@@ -350,7 +350,6 @@ SB: Receive Message No Timeout,cSB4306,"Upon receipt of a Request to receive a S
 SB: Receive Message With Timeout,cSB4307,"Upon receipt of a Request to receive a SB Message from a Pipe with a pending timeout, the cFE shall suspend execution of the Application until a SB Message is present on the Pipe or the timeout has expired.","A receive Request with a suspension timeout provides a blocking method of retrieving SB messages. This is useful for data driven Applications and has been used on all heritage missions with a SB. The timeout is useful for fault recovery for Applications that always expect data to arrive or to allow periodic processing for Applications that are not purely data driven. If a SB Message is queued on the Pipe then the SB Message will be provided to the Application and the Application’s execution will not be suspended. Tasks that process telemetry packets often receive many types of packets from different sources.  There should be a mechanism that allows a task to wait for many different types of messages simultaneously.  Heritage implementations of SB do this by directing the messages into one queue (or several queues, to implement priority levels).
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 SB: Receive Message Infinite Timeout,cSB4308,"Upon receipt of a Request to receive a SB Message from a Pipe with an infinite timeout, the cFE shall suspend execution of the Application until a SB Message is present on the Pipe.",This mode of receiving has been the most commonly used mode on the heritage SB.
-SB: Last Message Sender Info,cSB4309,"Upon receipt of a Request, the cFE shall provide sender information for the last message received on an Application's Pipe.","Heritage SB did a 'valid senders check' before delivering a packet to a pipe. Since the cFE supports a dynamic environment and the sender of a packet is somewhat unknown, the cFE must provide a means for the application to do the 'valid sender check'."
 SB: Get Message ID,cSB4311,"Upon receipt of a Request, the cFE shall provide the message ID of the requested message.",Message management utility.
 SB: Set Message ID,cSB4312,"Upon receipt of a Request, the cFE shall set the received message with the received message ID.",Message management utility.
 SB: Get Message String,cSB4313,"Upon receipt of a Request, the cFE shall provide the requested string from the requested message.",Message management utility.