How to get the continuous current rating of a power led from the spec sheet?
The answer is in this chart on page 5 of the datasheet:



For pulse widths above 1 s, (which we can extrapolate out to DC operation), so long as you heat sink adequately to maintain a die temperature of 85 C (possibly slightly higher, but you definitely want to avoid run-away die temperature) the maximum current is 2 A.