[Legend] table layout - fix horizontal scrollbar caused by cell padding / sizing

[maryam-saeidi]

Related to: #2784 (review)

Summary

In legend “table” layout (typically when legend values are shown), the legend can render with unwanted horizontal scrollbars even when there should be enough space. This seems to be caused by sizing/padding in echLegendTable__cell making the table wider than its container.

@markov00 Can you please share a video of screenshot of this issue?

Notes / investigation hints

Removing/reducing padding on echLegendTable__cell and using a grid-gap style can eliminate the scrollbar, but it introduces a minor visual issue with the table header bottom border. The fix should address both: no scrollbar and header border remains correct/consistent.

Acceptance criteria

• Table layout legend does not show horizontal scrollbars in normal cases
• Spacing remains visually correct (cell padding/gaps) and header divider/border is not broken

[markov00]

Probably this was just a fluke, I've checked main again right now and I don't see this problem anymore.
The scrollbar arrives when the columns used by the LegendValues are of a size > then 50% of the legend size, so fine for now