fix: improve dependency dashboard text (#11050)

lib/platform/utils/__fixtures__/issue-body.txt

lib/platform/utils/read-only-issue-body.ts

...repository/__fixtures__/master-issue_with_2_PR_edited.txt

...itory/__fixtures__/master-issue_with_3_PR_in_approval.txt

...itory/__fixtures__/master-issue_with_3_PR_in_progress.txt

...orkers/repository/__fixtures__/master-issue_with_8_PR.txt

...epository/__snapshots__/dependency-dashboard.spec.ts.snap

lib/workers/repository/dependency-dashboard.ts