Sorting by lines doesn't work

[e-for-eshaan]

Description:

Clicking on the LINES header on the PR table doesn't sort correctly

Steps to reproduce:

1. Go to /dora-metrics
2. Click lead-time stats card
3. in the PR table beneath, try sorting by number of lines

Expected behavior:

• should sort perfectly by number of lines

Actual behavior:

• sort is broken

Server Setup Information:

• Operating System:
• Deployment Method:

Additional context

[KartikChawla09]

The conf.field is labelled as additions but line changes actually is the sum of additions and deletions. I am working towards fixing this issue.