docs: drop removed pr_number input from apply.yml dispatch example

[Svaag]

What

Follow-up to #437. Grepping the repo for stale apply.yml pr_number callers
(the input was removed in #432) turned up one last reference — a doc example,
not a workflow caller:

docs/ci/deploy-runbook.md showed:

gh workflow run apply.yml \
  -F playbook=noc -F limit=noc -F dry_run=false \
  -F pr_number=42         # optional — auto-comments the diff onto the PR

Running that today errors on an unexpected input. Removed the flag and the
matching "/ PR" UI hint so the runbook matches apply.yml's current inputs
(playbook / limit / dry_run).

Verification

grep -rn pr_number across the repo now returns zero references — no
workflow callers (only app-promotion-deploy.yml calls apply.yml, fixed in
#437) and no docs.

🤖 Generated with Claude Code

[github-actions]

PR Reviewer Guide 🔍

Here are some key observations to aid the review process:

🎫 Ticket compliance analysis 🔶 437 - Partially compliant Compliant requirements: None. The PR does not touch workflow files; it only updates a documentation example. Non-compliant requirements: Does not remove pr_number from firewall job in app-promotion-deploy.yml. Does not fix the workflow startup failure. 432 - Partially compliant Compliant requirements: Removes a stale pr_number reference from docs/ci/deploy-runbook.md doc example. Non-compliant requirements: Does not remove the Icinga deploy-snapshot mechanism from playbooks, roles, or configs. Does not modify apply.yml or app-promotion-deploy.yml workflow files. Does not delete test scripts or CI hooks.

⏱️ Estimated effort to review: 1 🔵⚪⚪⚪⚪

🏅 Score: 95

🧪 No relevant tests

🔒 No security concerns identified

⚡ No major issues detected

[github-actions]

PR Code Suggestions ✨

No code suggestions found for the PR.