Optimize scrolling behavior of Discover table (#7017)

* Optimize scrolling behavior of Discover table

This is an improvement to #6683

Signed-off-by: Miki <miki@amazon.com>
(cherry picked from commit ebe2b9f)
Signed-off-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

src/plugins/discover/public/application/components/default_discover_table/default_discover_table.tsx

@@ -180,6 +180,10 @@ const DefaultDiscoverTableUI = ({
     if (tableElement) {
       // Load the first batch of rows and adjust the columns to the contents
       tableElement.style.tableLayout = 'auto';
+      // To prevent influencing the auto-sizing, unset the widths from a previous render
+      tableElement.querySelectorAll('thead > tr > th:not(:first-child)').forEach((th) => {
+        (th as HTMLTableCellElement).style.width = 'unset';
+      });
 
       tableLayoutRequestFrameRef.current = requestAnimationFrame(() => {
         if (tableElement) {