parametrise tolerance_s in visualize_dataset scripts

[eaa3]

What this does

Hi guys, this is a simple PR adding an optional argument for the tolerance_s parameter when visualising a LeRobotDataset.
This should make the visualisation a bit more flexible if you want to relax that threshold when visualising test data, etc.

Examples:

Title	Label
Improve visualization script	(⚡️ Minor improvement)

How it was tested

Explain/show how you tested your changes.

Examples:

• You can quickly try by running the examples bellow.

How to checkout & try? (for the reviewer)

Provide a simple way for the reviewer to try out your changes.

Examples:

python -m lerobot.scripts.visualize_dataset --episode-index 0  --repo-id lerobot/pushT --tolerance-s 0.1

Example without tolerance parameter being chosen (default matches LeRobotDataset tolarance_s=1e-4)

python -m lerobot.scripts.visualize_dataset --episode-index 0  --repo-id lerobot/pushT

Same is valid for the html visualiser:

python -m lerobot.scripts.visualize_dataset_html --repo-id lerobot/pushT --port 9090 --tolerance-s 0.1

Example without tolerance parameter being chosen (default matches LeRobotDataset tolarance_s=1e-4)

python -m lerobot.scripts.visualize_dataset_html --repo-id lerobot/pushT --port 9090

[eaa3]

cc: @aliberts @Cadene