fix: malformed citation urls

[AdityaHegde]

Sometimes citation urls have additional brackets in the end. The guess is, the response generation gets messed up when the url itself has brackets and it gets appended to the url. This tries to prevent it by using base64 proto instead of url encoded json for url params.

Closes APP-493

Checklist:

• Covered by tests
• Ran it and it works as intended
• Reviewed the diff before requesting a review
• Checked for unhandled edge cases
• Linked the issues it closes
• Checked if the docs need to be updated. If so, create a separate Linear DOCS issue
• Intend to cherry-pick into the release branch
• I'm proud of this work!