feat: Chain displays the total number of C atoms during mouseMove

[mySkey]

How the feature works? / How did you fix the issue?

(Screenshots, videos, or GIFs, if applicable)

The chain displays the total number of C atoms during mouseMove, and follows the original logic during mouseUp because we need to know the length of the chain, otherwise we have to count them one by one

Check list

• unit-tests written
• e2e-tests written
• documentation updated
• PR name follows the pattern #1234 – issue name
• branch name doesn't contain '#'
• PR is linked with the issue
• base branch (master or release/xx) is correct
• task status changed to "Code review"
• reviewers are notified about the pull request

[svvald]

Hello @mySkey, thank you for your contribution! This is a valuable improvement, which definitely comes in handy. While the overall implementation looks good and we will certainly use it, we also need to discuss it within our team, probably we might want to come up with a slightly different appearance for atoms counter

ETA on delivering this feature in the upcoming release is mid-January, please let us know if it's critical for you current operations, we might be able to prepare a dev release for you