fix(DiffView): Ensure ranges are initialized when landing

[grafakus]

✨ Description

Related issue(s): -

I've noticed a weird bug on the "Diff flame graph view" where ranges were not preserved. Here are 2 short videos before/after:

Before (currently in main)	After (what this PR fixes)
https://github.com/user-attachments/assets/2823fbc8-cd60-459c-a464-dc5ba2990d28	https://github.com/user-attachments/assets/2e1be5cb-9fa8-40a8-9976-6920b4c2a250

Through git bisect I was able to pinpoint this commit as the culprit.

📖 Summary of the changes

To be totally honest, I still don't fully understand why it happened and why this PR fixes it.

🧪 How to test?

• The build should pass
• Locally, after checking out this PR

[github-actions[bot]]

Unit test coverage

Lines	Statements	Branches	Functions
	11.6% (433/3730)	9.1% (121/1329)	8.59% (102/1187)