The input current sense is necessary for input current regulation loop. Input current regulation can help keep the input voltage from collapsing, and provide more power output to the system and battery. If the input current regulation is disabled by shorting the sense pins, then under heavy loading, the input voltage will collapse to the input voltage regulation point (~4.5V). This will greatly limit the output power capability of the MAX77962.
If the application is using a fixed 5V input, or has very high input current limit on the source, then shorting the input current sense pins is acceptable.