[Tests] Reduce export test problem size

Reduce parameter sizes for export test to reduce test time.

aidge_core/unit_tests/test_export.py

@@ -78,14 +78,14 @@ class test_export(unittest.TestCase):
         model = aidge_core.sequential(
             [
                 aidge_core.FC(
-                    in_channels=32 * 32 * 3, out_channels=512, name="InputNode"
+                    in_channels=32 * 32 * 3, out_channels=64, name="InputNode"
                 ),
                 aidge_core.ReLU(name="Relu0"),
-                aidge_core.FC(in_channels=512, out_channels=256, name="FC1"),
+                aidge_core.FC(in_channels=64, out_channels=32, name="FC1"),
                 aidge_core.ReLU(name="Relu1"),
-                aidge_core.FC(in_channels=256, out_channels=128, name="FC2"),
+                aidge_core.FC(in_channels=32, out_channels=16, name="FC2"),
                 aidge_core.ReLU(name="Relu2"),
-                aidge_core.FC(in_channels=128, out_channels=10, name="OutputNode"),
+                aidge_core.FC(in_channels=16, out_channels=10, name="OutputNode"),
             ]
         )