Use @ucam.uis.devops/mui-theme

Description

This task is to use the @ucam.uis.devops/mui-theme in our application.

Further details

Since @ucam.uis.devops/mui-theme requires "@mui/material": "^7.0.0", this probably means we first want to upgrade @mui/material from v6 to v7. This can be done in a separate MR.

Task list

• Bump @mui/material to v7
• Adopt @ucam.uis.devops/mui-theme

Acceptance criteria

• Application uses @ucam.uis.devops/mui-theme

Links/references

• https://gitlab.developers.cam.ac.uk/uis/devops/lib/mui-theme/-/tree/main?ref_type=heads