Update test utils selectors snapshots

Author: jperals

src/__tests__/snapshot-tests/__snapshots__/test-utils-selectors.test.tsx.snap

@@ -565,7 +565,6 @@ exports[`test-utils selectors 1`] = `
   "split-panel": [
     "awsui_close-button_rjqu5",
     "awsui_header-actions_rjqu5",
-    "awsui_header-before_rjqu5",
     "awsui_header-description_rjqu5",
     "awsui_header-info_rjqu5",
     "awsui_header-text_rjqu5",