Docs build bug fixes

[kingsleynweye]

Description

Bug fixes for docs build.

Issue

NIL

Changes

• Added installation of test requirements to sphinx build.

Screenshots

NIL

Checklist

• [x] I have tested the changes locally and they work as intended.
• [x] I have updated the documentation, if applicable.
• [ ] I have added new tests, if applicable.
• [x] I have added any required dependencies to the requirements.txt file, if applicable.
• [x] I have followed the project's code style and conventions.

Additional notes

NIL