chromiumBeta: Install crashpad_handler

This executable is required to fix a startup error.
TODO: Refactor the Nix expressions to allow chromiumVersionAtLeast, etc.
"everywhere" and investigate the VM test failure.

(cherry picked from commit ef7f020ec88c6aa92f3c35a4a83cd3517533d690)

pkgs/applications/networking/browsers/chromium/browser.nix

@@ -62,7 +62,7 @@ mkChromiumDerivation (base: rec {
       -e '/\[Desktop Entry\]/a\' \
       -e 'StartupWMClass=chromium-browser' \
       $out/share/applications/chromium-browser.desktop
-  '' + lib.optionalString (channel == "dev") ''
+  '' + lib.optionalString (channel != "stable") ''
     cp -v "$buildPath/crashpad_handler" "$libExecPath/"
   '';