Accept numbers serialized as strings

Updates `deserialize` to accept numeric values encoded as strings. 

This occurs when JSON serialization a dictionary with `int` or `float` keys. To handle a dictionary, JSON converts the value into an object. Objects must have string-valued keys, so the numbers are encoded i.e. `str(x)` for any `x` that is a dictionary key.

The updated final deserialization case now attempts to perform this specific deserialization route before testing the existing numerical deserialization routes. New test cases are present to check for this new behavior.

core_utils/serialization.py

@@ -210,15 +210,25 @@ def deserialize(
         return type_value[value]  # type: ignore
 
     else:
+
         # Check to see that the expected value is present & has the expected type,
         # iff the expected type is one of JSON's value types.
         if (
             (value is None and not _is_optional(checking_type_value))
             or (any(map(lambda t: t == type_value, (int, float, str, bool))))
             and not isinstance(value, checking_type_value)
         ):
+            fail = False
+            # exception: encoded a number into a string; attempt trivial decoding to avoid failure
+            # JSON will encode numbers that are dictionary keys as strings
+            # so that it can make them compliant as objects.
+            if issubclass(checking_type_value, Number) and isinstance(value, str):
+                try:
+                    value = type_value(value.strip())
+                except ValueError:
+                    fail = True
             # numeric check: some ints can be a float
-            if (
+            elif (
                 float == type_value
                 and isinstance(value, int)
                 and int(float(value)) == value
@@ -230,6 +240,9 @@ def deserialize(
             # but in general we just identified a value that
             # didn't deserialize to its expected type
             else:
+                fail = True
+
+            if fail:
                 raise FieldDeserializeFail(
                     field_name="", expected_type=type_value, actual_value=value
                 )