Fix uninstaller missing recent changes

- group unsupported formats into the same code (86f778c0aa (diff-93690a8d9f50c177ef97416af3be8726))
- support A only system-as-root devices (e72c6685ed (diff-93690a8d9f50c177ef97416af3be8726))
- remove unnecessary '--' from magiskboot actions (7f08c06943 (diff-93690a8d9f50c177ef97416af3be8726))
- get_flags need to be before find_boot_image (a4f5d47e72)

closes #1371, closes #1431, closes #1439

app/src/main/res/raw/utils.sh

@@ -55,6 +55,7 @@ restore_imgs() {
   local STOCKDTBO=/data/stock_dtbo.img.gz
   [ -f $STOCKBOOT ] || return 1
 
+  get_flags
   find_boot_image
   find_dtbo_image