fuel_gauge: Add fuel_guage_set_props()

The fuel_gauge_set_prop() function prototype declares a function that sets
multiple fuel gauge properties at once. The naming suggests it ought to
fetch a singular property at a time. Moreso, some clients may just want to
set properties one at a time and may feel uncomfortable using a prototype
for fetching multiple properties when wanting to fetch them one at a time.

Modify fuel_gauge_set_prop() to fetch a single property and add
fuel_gauge_set_props() to support fetching multiple properties. Modify
existing tests/drivers/samples.

This is part of #61818 work.

Signed-off-by: Aaron Massey <aaronmassey@google.com>