rainfall dataset resolution is too coarse

[dfguerrerom]

The rainfall dataset is too coarse and presents errors when small areas are processed, triggering a non-sense error to the end user:

File ~/1_modules/se.plan/component/scripts/gee.py:71, in <genexpr>(.0)
     67 print("values", values)
     68 # depending on the scale, values from the histogram can be floats, we'll
     69 # convert them to integers... sometimes we'll show more values than the
     70 # asset really have
---> 71 return sorted(set(int(float(val)) for val in values))

TypeError: float() argument must be a string or a real number, not 'NoneType'

we should display a more meaningful error and definitely find another precipitation data source.

@andreamcmahon