feat(ACI): Make rule stats and group history endpoints backwards compatible

[ceorourke]

Redo of #110282 to make the rule stats and group history endpoints backwards compatible by being flexible enough to handle either a Rule or a Workflow. The previous PR was reverted because I incorrectly assumed Rule objects were using RuleFireHistory, but it is correct to continue to combine those results with WorkflowFireHistory for now.

For both methods the basic logic is as follows:

• If passed a workflow, try to fetch the rule ID via AlertRuleWorkflow and fetch combined results. If the workflow was single written, fetch WorkflowFireHistory results only.
• If passed a rule, try to fetch the workflow via AlertRuleWorkflow and fetch combined results. If the rule for some reason doesn't have a workflow, fetch RuleFireHistory results only (this maintains the existing behavior).

[linear-code]

ISWF-2190 Rule details page not rendering

[kcons]

LG, haven't dug too far into the test coverage though.
I don't think it'd be crazy to use a single query that still supports Rules; if we're not passing an ID, it's a no-op, and it's easy enough to adjust the query once we don't want to mention Rules ever again.

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}