MANDIANT_ACTIVE_BREACH_IOC,MANDIANT_FUSION_IOC, andOPEN_SOURCE_INTEL_IOC` feeds are being removed

## Deprecate Deprecated **MANDIANT\_ACTIVE\_BREACH\_IOC`,`MANDIANT\_FUSION\_IOC`, and`OPEN\_SOURCE\_INTEL\_IOC\` feeds are being removed** The `MANDIANT_ACTIVE_BREACH_IOC`, `MANDIANT_FUSION_IOC`, and `OPEN_SOURCE_INTEL_IOC` feeds are [deprecated](https://cloud.google.com/chronicle/docs/deprecations) in favor of the `GTI_IOC` feed. After March 18, 2027, we will be removing the `MANDIANT_ACTIVE_BREACH_IOC`, `MANDIANT_FUSION_IOC`, and `OPEN_SOURCE_INTEL_IOC` feeds. For more information on how to migrate, see [Migrate Mandiant legacy feeds to GTI](https://cloud.google.com/chronicle/docs/detection/ati-fusion-feed#migrateToGTI).