MDEV-34919 - Aria crashes with high-level (vector) indexes

[svoj]

• The Jira issue number for this PR is: MDEV-34919

Description

Fixes aria crash with high-level indexes.

Release Notes

None.

How can this PR be tested?

mtr vector

Basing the PR against the correct MariaDB version

• This is a new feature or a refactoring, and the PR is based against the main branch.
• This is a bug fix, and the PR is based against the earliest maintained branch in which the bug can be reproduced.

PR quality check

• I checked the CODING_STANDARDS.md file and my PR conforms to this where appropriate.
• For any trivial modifications to the PR, I am ok with the reviewer making the changes themselves.

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