feat: use new magic value for FIL_RESERVED on calibnet after nv25 is enabled

[lemmih]

Summary of changes

Changes introduced in this pull request:

• Use new magic value on calibnet after NV25

Reference issue to close (if applicable)

Closes #5348

Other information and links

Change checklist

• I have performed a self-review of my own code,
• I have made corresponding changes to the documentation. All new code adheres to the team's documentation standards,
• I have added tests that prove my fix is effective or that my feature works (if possible),
• I have made sure the CHANGELOG is up-to-date. All user-facing changes should be reflected in this document.

[LesnyRumcajs]

Let's hold off with merging this until we know for sure that FIP-0100 will be included in NV25. I believe there are still some ongoing discussions.

[hanabi1224]

We might want to implement filecoin-project/lotus#12938 as well