fix hover event not triggered on consecutive empty bins (count=0) with hovermode:'x' for histogram

[Lexachoc]

This PR fixes #7502

Description

Fixes a bug where hovermode:'x' (this PR also works for other hovermodes like 'x unified', 'y', 'y unified') on histogram would not trigger hover events over consecutive zero-count bins.
Previously, hovering over empty bins would keep reporting the first empty binNumber, causing stale hover data and breaking expected behavior.

Changes

Ensure hover events fire consistently across all empty bins. Correctly report the actual binNumber (and trigger hover event).

Before & After

See the fixed look in #7502 (comment)

[camdecoster]

@Lexachoc thanks for the bug and fix! In the future, could you please add a description and list of changes? Your bug report contains a good deal of information, but it would be helpful to have some of that in the PR. I always appreciate a one line fix. I added one small suggestion and I wrote a test for this situation (based on your Pen). Good work!

[Lexachoc]

@Lexachoc thanks for the bug and fix! In the future, could you please add a description and list of changes? Your bug report contains a good deal of information, but it would be helpful to have some of that in the PR. I always appreciate a one line fix. I added one small suggestion and I wrote a test for this situation (based on your Pen). Good work!

Thanks for the review and test! I've changed according to your suggestion.