Fix editable-install patch for 26.05 + unblock icon in unprivileged build

The previous patch matched a development-branch variable that does not
exist in release 2605.0, so the warning fired and the editable install was
not patched. In 2605.0 the -e is hardcoded in the pip command
("pip install -e ${package_folder_path}"); strip the -e there instead.

Also, flatpak build-export validates exported app icons in a bwrap sandbox,
which fails in an unprivileged container. Keep the icon inside the app (for
the running window/taskbar) but remove it from build-dir/export so export
skips validation. Host menu icon stays generic; build needs no privileges.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

org.o3de.O3DE.yaml

@@ -43,10 +43,10 @@ modules:
       - |
         set -e
         LYPYTHON=$(find "${FLATPAK_DEST}/opt/O3DE" -path '*/cmake/LYPython.cmake' | head -n1)
-        if [ -n "$LYPYTHON" ] && grep -q 'set(_pip_install_mode_args "-e")' "$LYPYTHON"; then
-          sed -i 's/set(_pip_install_mode_args "-e")/set(_pip_install_mode_args "")/' "$LYPYTHON"
+        if [ -n "$LYPYTHON" ] && grep -qF -- '-m pip install -e ' "$LYPYTHON"; then
+          sed -i 's/-m pip install -e /-m pip install /g' "$LYPYTHON"
         else
-          echo "::warning:: editable-install line not found in LYPython.cmake"
+          echo "::warning:: 'pip install -e' not found in LYPython.cmake"
         fi
       # Launcher + AppStream + desktop entry under the Flatpak app-id.
       - install -Dm755 o3de-wrapper.sh "${FLATPAK_DEST}/bin/o3de-wrapper.sh"