Fix `blocked` status for board issues

What does this MR do?

IssueLink relations are bidirectional - IOW source can block target but also target can be blocked by source. We want to show blocked: true in both of these cases. Also this MR removes permission check - IOW we show blocked status no matter if user can access the blocking issue (more details in related issue).

DB query plan:

For the first list on this board the query should look like this: https://gitlab.com/snippets/1939809

Execution plan: https://explain.depesz.com/s/1D4a

Related to #202067 (closed)

Related to #196803 (comment 283786151)

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team