js/graph.js, tests: add 'reads'

21 jobs for feature-c/4370-label-tooltip-graph in 25 minutes and 42 seconds (queued for 4 seconds)
Name Stage Failure
failed
code_quality Test Quality
$ function propagate_env_vars() { # collapsed multi-line command
$ docker pull --quiet "$CODE_QUALITY_IMAGE"
unknown flag: --quiet
See 'docker pull --help'.
Uploading artifacts...
Runtime platform arch=386 os=linux pid=7809 revision=58272c27 version=12.7.0
WARNING: gl-code-quality-report.json: no matching files
ERROR: No files to upload
ERROR: Job failed: exit status 1