Fix: Use 2025 Italy GP session to show legacy line in docs

[TracingInsights]

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[theOehrly]

Is the main reason for this just to use a more recent season or is there something else?

[TracingInsights]

legacy line is missing from the chart in docs at https://docs.fastf1.dev/api_reference/legacy/legacy.html

[theOehrly]

Sorry for the delay. I had wanted to look at this in more detail and then I forgot about your PR instead 😅

I was wondering what caused this problem in the first place. Why did this change at some point? I did look at this a bit more just now. And so far I haven't been able to figure out what's going wrong.
Now, applying your change, both lines are shown again. But they are very different to the point where at least one of them has to be very wrong. So I don't really want to merge this right now. I assume that the newer implementation is more correct, since I wrote it for that reason. And maybe it's just time to get rid of the legacy method. I don't want to spend time fixing it and if it's very wrong, it should go.

But I'd still like to figure out what's the problem here. Therefore, I'll leave this open for now and I'll plan to look at this again.