save a request in the github info cog when fetching pulls

[onerandomusername]

Description

https://github.com/python-discord/sir-lancebot/blob/c8526d7935ee37389d10b03e833ccdeb2faa5101/bot/exts/utilities/githubinfo.py#L123-L125

This data is provided in the issue body under the pull_request key. We don't need to fetch a second time.

Reasoning

This will halve the requests used to look up a pull request, which stacks when looking up 2 or 3 pull requests at a time.

Proposed Implementation

Additional Details

Would you like to implement this yourself?

• [x] I'd like to implement this feature myself
• [ ] Anyone can implement this feature

[ChrisLovering]

Sounds good to me!