Fix Integer overflow in estimateCuesSize

With a 200GB SD Card the Camera reported an expected max file duration
of 89158000000 us. This number will cause an overflow in estimating the
size of the file. Fix this by calculating the size on a long double and
then assigning a limited value to size.

Bug: 352217637
Test: atest StagefrightRecorderTest
Change-Id: Ibb17ece0fe6ea80abfeaa12a054db7cf40fff90e