fix: use 0600 perms for tmp files for post analyzers

[DmitriyLewen]

Description

Use 0600 perms for tmp files for post analyzers to avoid errors when file use wrong perms.
e.g.:

• Image scan error: open analyzer-fs permission denied #6373
• After upgrading to v2.8.2 version, getting unexpected status code: 500, expected: 200 error for scan goharbor/harbor#18824
• Harbor scan giving error for fluent/fluentd:v1.16.2-windows-ltsc2019-1.0 goharbor/harbor#19405

Related issues

• Close Image scan error: open analyzer-fs permission denied #6373

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).