Replace deprecated 'unload' with modern 'pagehide' event listener#2130

bschwarzent wants to merge 1 commit intoreleases/24.2eclipse-scout/scout.rt:releases/24.2from

features/bsh/24.2/454776_unload_pagehideeclipse-scout/scout.rt:features/bsh/24.2/454776_unload_pagehideCopy head branch name to clipboard