fix: replace funk reference in syscall handler with sysvar cache look…

[beesyst]

Summary

Refactored the get_sysvar syscall handler to use the sysvar cache instead of direct funk access, ensuring SVM remains pure and decoupled from storage/database APIs.

Scope

• Affected files: fd_vm_syscall_runtime.c, fd_bank_abi.c
• All other funk/database references untouched

Reason

Fixes a rare layering violation (see #5030), keeping SVM logic isolated from db/storage code.

Testing

• Local build and all tests pass
• Verified all get_sysvar calls use the cache
• Ran clang-format / linter

[ripatel-fd]

Thank you for the contribution @beesyst. We are not ready to accept PRs for this area, since we are working on a rather big refactor for sysvar memory management: #5506

[beesyst]

Thank you for the contribution @beesyst. We are not ready to accept PRs for this area, since we are working on a rather big refactor for sysvar memory management: #5506

Got it, thx.