manifest: drop external/update_binary, duplicates bootable/deprecated-ota

This AOSP release didn't actually delete applypatch/edify/updater --
it relocated them, still Soong-converted, to bootable/deprecated-ota/.
Syncing external_update_binary alongside it produced a hard Soong
module-name collision (identical module names, several with matching
line numbers -- external_update_binary appears to be a near-verbatim
copy). Nothing currently wires either copy's modules into
PRODUCT_PACKAGES, so dropping the duplicate is a pure fix.

common/pawletos.xml

@@ -13,8 +13,14 @@
 
   <!-- Recovery — stock bootable/recovery stays unforked, TWRP GUI/toolkit plug in via
        vendor/pawlet/recovery_ui + vendor/pawlet/recovery_toolkit (already synced as part of
-       vendor/pawlet below, no separate project needed). See NOTES-ota-recovery-ab.md. -->
-  <project path="external/update_binary" name="PawletOS/external_update_binary" remote="oxmc_git" revision="android-16.0" />
+       vendor/pawlet below, no separate project needed). See NOTES-ota-recovery-ab.md.
+
+       external/update_binary (PawletOS/external_update_binary) is NOT synced: it duplicates
+       applypatch/edify/updater, which this AOSP release already ships, Soong-converted, at
+       bootable/deprecated-ota/, confirmed by a hard Soong module-name collision the one time
+       both were synced together. Nothing in PawletOS currently references either copy's
+       modules from PRODUCT_PACKAGES; when non-A/B OTA wiring actually happens, point it at
+       bootable/deprecated-ota's existing modules instead of reviving this project. -->
   <!-- Vendor (HALs, system apps, etc.) -->
   <project path="vendor/pawlet" name="PawletOS/android_vendor_pawlet" remote="oxmc_git" revision="android-16.0" />