Make felt_from_number report errors properly

instead of returning Ok(None) in case of an error

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 #### Upcoming Changes
 
+* Fix felt_from_number not properly returning parse errors [#1012](https://github.com/lambdaclass/cairo-rs/pull/1012)
+
 * Add missing hint on vrf.json lib [#1052](https://github.com/lambdaclass/cairo-rs/pull/1052):
 
     `BuiltinHintProcessor` now supports the following hint:

src/serde/deserialize_program.rs

@@ -162,7 +162,10 @@ where
     D: Deserializer<'de>,
 {
     let n = Number::deserialize(deserializer)?;
-    Ok(Felt252::parse_bytes(n.to_string().as_bytes(), 10))
+    match Felt252::parse_bytes(n.to_string().as_bytes(), 10) {
+        Some(x) => Ok(Some(x)),
+        None => Err(String::from("felt_from_number parse error")).map_err(de::Error::custom),
+    }
 }
 
 #[derive(Serialize, Deserialize, Debug, PartialEq, Eq, Clone)]
@@ -1345,4 +1348,16 @@ mod tests {
             "()"
         );
     }
+
+    #[test]
+    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+    fn deserialize_nonbase10_number_errors() {
+        let valid_json = r#"
+        {
+            "value" : 0x123
+        }"#;
+
+        let iden: Result<Identifier, serde_json::Error> = serde_json::from_str(valid_json);
+        assert!(iden.err().is_some());
+    }
 }