android build: restore prev "make theming" behaviour

- note: "make theming" is kivy-specific, and not needed for the qml gui apk
- note: "make theming" does not run automatically as part of the build scripts,
        although it used to in the past. For reproducible builds, the
        "electrum/gui/kivy/theming/atlas" git submodule contains the build
        artefacts. However, the user is supposed to manually run "make theming"
        when changing the atlas/images.

contrib/android/Makefile

@@ -25,7 +25,7 @@ export BUILD_TIME         := $(shell LC_ALL=C TZ=UTC date +'%H:%M:%S' -d @$(SOUR
 
 theming:
 	#bash -c 'for i in network lightning; do convert -background none theming/light/$i.{svg,png}; done'
-	#$(PYTHON) -m kivy.atlas ../../electrum/gui/kivy/theming/atlas/light 1024 ../../electrum/gui/kivy/theming/light/*.png
+	$(PYTHON) -m kivy.atlas ../../electrum/gui/kivy/theming/atlas/light 1024 ../../electrum/gui/kivy/theming/light/*.png
 prepare:
 	# running pre build setup
 	# copy electrum to main.py