fix(ci): avoid pipefail in ci.yaml shell code

[juenglin]

Issue: ci failures like this

The CI failure is a classic SIGPIPE + pipefail interaction.

The original code pipes gh api --paginate into head -1. Under bash -o pipefail
(set by the shell option in the step), when head -1 reads one line and exits, it
closes the pipe. gh api then receives SIGPIPE (exit 141), and pipefail propagates
that non-zero exit code through the command substitution, causing the step to fail
under set -e.

The fix avoids this by:

1. Collecting all output into an array via mapfile (no pipe to break).
2. Using || true to suppress any transient gh api exit code from the process substitution.
3. Taking the first element with ${_tags[0]:-} instead of head -1.

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