Use is_close_to_zero() instead of math.isclose(..., abs_tol=...)

We already have an utility function to check if a `float` is close
to zero, so we can use that instead.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

src/frequenz/sdk/power/_distribution_algorithm.py

@@ -400,9 +400,9 @@ def _distribute_power(  # pylint: disable=too-many-arguments
             distribution[inverter.component_id] = excl_bound
 
         for inverter_id, deficit in deficits.items():
-            while not math.isclose(deficit, 0.0, abs_tol=1e-6) and deficit < 0.0:
+            while not is_close_to_zero(deficit) and deficit < 0.0:
                 take_from = max(excess_reserved.items(), key=lambda item: item[1])
-                if math.isclose(take_from[1], 0.0, abs_tol=1e-6) or take_from[1] < 0.0:
+                if is_close_to_zero(take_from[1]) or take_from[1] < 0.0:
                     break
                 if take_from[1] >= -deficit or math.isclose(
                     take_from[1], -deficit, abs_tol=1e-6