The MAX96706 datasheet lists the worst case currents for AVDD + DVDD on page 11 of the datasheet*. AVDD and DVDD are both 1.8V supplies, so the assumption is that they will be powered by the same 1.8V rail. Measuring the total current drawn by both at the same time makes it easier to budget enough output current for the MAX96706 from the 1.8V rail.
* MAX96706 datasheet rev. 2 (11/18), valid as of April 2019