ci(spdx): add aqua-installer step to fix mage error

[DmitriyLewen]

Description

We added cron workflow to check SPDX License exceptions (#8077).
But i forgot to install aqua-installer.

This PR added this step.
Test run - https://github.com/DmitriyLewen/trivy/actions/runs/13150768822/job/36697700228

Related PRs

• fix(spdx): use the hasExtractedLicensingInfos field for licenses that are not listed in the SPDX #8077

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).