`sentinel`: `metadataThreatAnalysisTactics` of `metadata` lacks enum definition

[`metadataThreatAnalysisTactics`](https://github.com/Azure/azure-rest-api-specs/blob/main/specification/securityinsights/resource-manager/Microsoft.SecurityInsights/stable/2023-02-01/Metadata.json#L577) is an enum property but only defined as string

Open specification/securityinsights/resource-manager/Microsoft.SecurityInsights/stable/2023-02-01/Metadata.json and inspect metadataThreatAnalysisTactics at line 577 alongside nearby enum properties. Confirm the expected enum definition from the surrounding specification conventions, update the property accordingly, and run the repository’s relevant specification validation checks to verify it is emitted as an enum.

Written by the indexing model from the issue text.