fix(ci): encrypt SARIF artifacts

[moghit-eou]

• Encrypt the merged SARIF with gpg before upload.
• Skip with a warning when ARTIFACT_PASSWORD is unavailable (Dependabot, fork PRs).
• One merged Security tab upload per pipeline instead of one per tool.

Before merge: add an ARTIFACT_PASSWORD repository secret.
Decrypt an artifact with:

gpg --decrypt --output report.sarif <name>.sarif.gpg

Also adds overrides for less (^4.9.0, drops the vulnerable image-size),
fast-uri and qs, which clears the SCA findings that were failing the gate.

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[github-advanced-security]

You are seeing this message because GitHub Code Scanning has recently been set up for this repository, or this pull request contains the workflow file for the Code Scanning tool.

What Enabling Code Scanning Means:

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• Depending on your configuration and choice of analysis tool, future pull requests will be annotated with code scanning analysis results.
• You will be able to see the analysis results for the pull request's branch on this overview once the scans have completed and the checks have passed.

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