SUSE-SU-2025:4406-1

This update for postgresql15 fixes the following issues:

Upgraded to 15.15:

• CVE-2025-12817: Fixed missing check for CREATE privileges on the schema in CREATE STATISTICS (bsc#1253332)
• CVE-2025-12818: Fixed integer overflow in allocation-size calculations within libpq (bsc#1253333)

Other fixes:

• Use %product_libs_llvm_ver to determine the LLVM version.
• Remove conditionals for obsolete PostgreSQL releases.
• Sync spec file from version 18.