Fix osu-framework submodule: point to valid master commit (8097681)

The submodule was pointing to commit c85f1debf4 which doesn't exist
in the winnerspiros/osu-framework remote (likely created locally but
never pushed). Update to the latest master (8097681) which includes
all critical fixes: DrawFrame surface guard, veldrid-spirv fork,
NRE fixes, perf optimizations, and iOS pack fixes.

Co-authored-by: winnerspiros <1675249+winnerspiros@users.noreply.github.com>

Author: Copilot