Remove configuration in DF chemistry sample (#2045)

This configuration was added in #1700, but it has a wrong error budget
that is not compatible with the other configuration and the sample. I
removed it again for clarity.

samples/estimation/df-chemistry/chemistry.py

@@ -493,11 +493,7 @@ def ndarray2d_to_string(arr):
             "errorBudget": 0.01,
             "qubitParams": {"name": "qubit_maj_ns_e6"},
             "qecScheme": {"name": "floquet_code"},
-        },
-        {
-            "qubitParams": {"name": "qubit_gate_us_e3"},
-            "estimateType": "frontier",
-        },
+        }
     ]
 else:
     params = []