Support checking for arbitrary options on .calls

Support checking for arbitrary options on .calls: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). However, I'm unable to test if those options are set correctly because fetch-mock removes them from the options list (as seen here…

The task

However, I'm unable to test if those options are set correctly because fetch-mock removes them from the options list (as seen [here](https://github.com/wheresrhys/fetch-mock/blob/527d170ecf86b0054d85acfcc7e015b332e78f6f/src/lib/request-utils.js#L41)).

Part of FineEnvs/MiMo-V2.6-RL-harbor-code.