Table: Fix edge case where text wrapping crashes on undefined header widths (#91850)

Make sure we don't read from header groups if it's undefined

packages/grafana-ui/src/components/Table/utils.ts

@@ -645,7 +645,7 @@ export function guessTextBoundingBox(
   lineHeight: number,
   defaultRowHeight: number
 ) {
-  const width = Number(headerGroup.width ?? 300);
+  const width = Number(headerGroup?.width ?? 300);
   const LINE_SCALE_FACTOR = 1.17;
   const LOW_LINE_PAD = 42;