fix: netcdf incorrect shape when using extract post-processors (#346)

## Description
Ensure data is post processed before open.

## What problem does this change solve?
Closes #341

Author: HCookie

src/anemoi/inference/outputs/netcdf.py

@@ -112,6 +112,8 @@ def open(self, state: State) -> None:
         with LOCK:
             self.ncfile = Dataset(self.path, "w", format="NETCDF4")
 
+        state = self.post_process(state)
+
         compression = {}  # dict(zlib=False, complevel=0)
 
         values = len(state["latitudes"])

src/anemoi/inference/outputs/plot.py

@@ -144,6 +144,7 @@ def write_step(self, state: State) -> None:
                 ekd.ArrayField(
                     values,
                     {
+                        "param": param,
                         "shortName": param,
                         "variable_name": param,
                         "step": state["step"],

src/anemoi/inference/outputs/tee.py

@@ -103,6 +103,8 @@ def open(self, state: State) -> None:
         state : State
             The state dictionary.
         """
+        state = self.post_process(state)
+
         for output in self.outputs:
             output.open(state)
 

src/anemoi/inference/outputs/zarr.py

@@ -160,6 +160,7 @@ def open(self, state: State) -> None:
         else:
             self.zarr_group = zarr.open_group(self.zarr_store, mode="w")
 
+        state = self.post_process(state)  # make sure state is post-processed
         values = len(state["latitudes"])
 
         time = 0