fix missing to_json export of computed_number_of_channels

The parameter was introduced in commit 9736f7c
but the export to_json was not added.

In the next commits, it is necessary to compute Raman gain during the design
phase. The sim-params used for this computation are updated during the
design phase for speed reasons. To ensure the proper restoration of user
settings for propagation, the export must include all parameters. Therefore,
this commit adds 'computed_number_of_channels' to the JSON export. This allows
for the accurate recording of all user settings locally and enables their
restoration.

Signed-off-by: EstherLerouzic <[email protected]>
Change-Id: I221a6f614010edea9cf46c3a7d43c5be064ff09c

gnpy/core/parameters.py

@@ -74,7 +74,8 @@ def to_json(self):
         return {"method": self.method,
                 "dispersion_tolerance": self.dispersion_tolerance,
                 "phase_shift_tolerance": self.phase_shift_tolerance,
-                "computed_channels": self.computed_channels}
+                "computed_channels": self.computed_channels,
+                "computed_number_of_channels": self.computed_number_of_channels}
 
 
 class SimParams(Parameters):