Exclude deleted projects from job token authorization logs graphql and csv export service

Related: https://gitlab.com/gitlab-org/gitlab/-/issues/560082

What does this MR do and why?

Since the background job responsible for handling the foreign key on ci_job_token_authorizations runs asynchronously and with some delay, the UI for CiJobTokenAuthLog can appear broken in the meantime.

As a result, the GraphQL query for auth logs fails with the error: "Cannot return null for non-nullable field CiJobTokenAuthLog.originProject"

This MR does the following:

• Excludes deleted or non-existent projects from JobTokenAuthLogsResolver.
• Excludes deleted or non-existent projects from Ci::JobToken::ExportAuthorizationsService used for the CSV download link.

References

Screenshots or screen recordings

Before	After

How to set up and validate locally

• Create 2 projects, project_a and project_b
• In project_a, add project_b to the allowlist
• Use project_b's CI_JOB_TOKEN to fetch anything from project_a
• Make sure that project_b shows up in the CI_JOB_TOKEN auth logs for project_a
• Delete project_b from the instance
• Now try to see the CI_JOB_TOKEN auth logs for project_a again

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