Fix default ivLength in dump-db tool

[Nriver]

The dump-db tool appears to be designed for a much older version of Trilium.

Related issue:
zadam/trilium#3017
Referencing this commit:
Commit Reference

At that time, the ivLength was incorrectly set to 13 instead of the correct value of 16. Consequently, if you attempt to use this tool to decrypt encrypted notes from the current database version, you will encounter errors because the tool's default ivLength remains at 13.

Code reference:
Source Code Reference

Error message:
Caught WRONG_FINAL_BLOCK_LENGTH, returning cipherText instead

To reproduce the issue, you can use the following test code:

npx esrun dump-db.ts --password 1234 document.db output/

To resolve this issue and ensure compatibility with the current database, the ivLength should be updated to a default value of 16.