[no_severity_nag] Exclude security bugs when nagging triage owner

[benjaminmah]

Resolves #2505.

Excludes any bugs with a security keyword to avoid nagging the triage owner.

Checklist

• Type annotations added to new functions
• Docs added to functions touched in main classes
• Dry-run produced the expected results
• The to-be-announced tag added if this is worth announcing

[benjaminmah]

Would it make sense to apply this filter to the other rules that nag the triage owner as well? (p1_no_activity.py, p1_no_assignee.py, etc.)

[marco-c]

Would it make sense to apply this filter to the other rules that nag the triage owner as well? (p1_no_activity.py, p1_no_assignee.py, etc.)

Which other rules do it? We could ask @mozfreddyb for each of them.

[benjaminmah]

Which other rules do it? We could ask @mozfreddyb for each of them.

Looking through the BugBot Wiki, the following are rules that NAG the triage owner:

• workflow/no_severity_nag.py
• workflow/p1_no_activity.py
• workflow/p1_no_assignee.py

There are other rules that NEEDINFO the triage owner, however.