Unset BROWSER for xdg-settings reads and don't abort removal on fallback failure

xdg-settings get also consults $BROWSER, so unset it for the getters too.
A failed best-effort fallback default should not abort the browser removal.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

bin/omarchy-default-browser

@@ -5,7 +5,7 @@
 # omarchy:examples=omarchy default browser firefox | omarchy default browser brave
 
 if (($# == 0)); then
-  case "$(xdg-settings get default-web-browser)" in
+  case "$(env -u BROWSER xdg-settings get default-web-browser)" in
   chromium.desktop) echo "chromium" ;;
   google-chrome.desktop) echo "chrome" ;;
   brave-browser.desktop) echo "brave" ;;
@@ -13,7 +13,7 @@ if (($# == 0)); then
   microsoft-edge.desktop) echo "edge" ;;
   firefox.desktop) echo "firefox" ;;
   zen.desktop) echo "zen" ;;
-  *) xdg-settings get default-web-browser ;;
+  *) env -u BROWSER xdg-settings get default-web-browser ;;
   esac
   exit 0
 fi