Bump Python version in mobile CI to 3.12.12

Update .github/workflows/mobile-forge.yml to use PYTHON_VERSION 3.12.12 (was 3.12.7). This applies a patch-level upgrade to the Python runtime used by the mobile CI workflow while keeping PYTHON_SHORT_VERSION at 3.12, ensuring CI picks up the latest bug and security fixes.

Author: FeodorFitsner

.github/workflows/mobile-forge.yml

@@ -6,7 +6,7 @@ on:
   workflow_dispatch:
 
 env:
-  PYTHON_VERSION: "3.12.7"
+  PYTHON_VERSION: "3.12.12"
   PYTHON_SHORT_VERSION: "3.12"
   MOBILE_FORGE_CACHE_DOWNLOADS_OFF: "1"
   NDK_VERSION: r27c