fix(dirt): add subscription cleanup to AllActivitiesService

Critical fix for production code quality and memory leak prevention.
Adds takeUntil pattern to all subscriptions to comply with ADR-0003
(Observable Data Services) requirements.

**Subscription Cleanup (ADR-0003 Compliance):**
- Add takeUntil pattern to AllActivitiesService subscriptions
- Add _destroy$ Subject and destroy() method
- Prevents memory leaks by properly unsubscribing from observables
- Follows Observable Data Services ADR requirements

Changes:
- Import Subject and takeUntil from rxjs
- Add private _destroy$ Subject for cleanup coordination
- Apply takeUntil(this._destroy$) to all 3 subscriptions:
  - enrichedReportData$ subscription
  - criticalReportResults$ subscription
  - newApplications$ subscription
- Add destroy() method for proper resource cleanup

This ensures proper resource cleanup and follows Bitwarden's
architectural decision records for observable management.

Related to PM-27284

bitwarden_license/bit-common/src/dirt/reports/risk-insights/services/view/all-activities.service.ts

@@ -1,4 +1,5 @@
-import { BehaviorSubject } from "rxjs";
+import { BehaviorSubject, Subject } from "rxjs";
+import { takeUntil } from "rxjs/operators";
 
 import { ApplicationHealthReportDetailEnriched } from "../../models";
 import { OrganizationReportSummary } from "../../models/report-models";
@@ -11,6 +12,8 @@ export class AllActivitiesService {
   /// Going forward, this class can be simplified by using the RiskInsightsDataService
   /// as it contains the application summary data.
 
+  private _destroy$ = new Subject<void>();
+
   private reportSummarySubject$ = new BehaviorSubject<OrganizationReportSummary>({
     totalMemberCount: 0,
     totalCriticalMemberCount: 0,
@@ -40,7 +43,7 @@ export class AllActivitiesService {
 
   constructor(private dataService: RiskInsightsDataService) {
     // All application summary changes
-    this.dataService.enrichedReportData$.subscribe((report) => {
+    this.dataService.enrichedReportData$.pipe(takeUntil(this._destroy$)).subscribe((report) => {
       if (report) {
         this.setAllAppsReportSummary(report.summaryData);
         this.setAllAppsReportDetails(report.reportData);
@@ -48,14 +51,14 @@ export class AllActivitiesService {
     });
 
     // Critical application summary changes
-    this.dataService.criticalReportResults$.subscribe((report) => {
+    this.dataService.criticalReportResults$.pipe(takeUntil(this._destroy$)).subscribe((report) => {
       if (report) {
         this.setCriticalAppsReportSummary(report.summaryData);
       }
     });
 
     // New applications changes (from orchestrator's reactive pipeline)
-    this.dataService.newApplications$.subscribe((newApps) => {
+    this.dataService.newApplications$.pipe(takeUntil(this._destroy$)).subscribe((newApps) => {
       this.setNewApplications(newApps);
     });
   }
@@ -108,4 +111,14 @@ export class AllActivitiesService {
       newApplications: newApps,
     });
   }
+
+  /**
+   * Cleanup method to prevent memory leaks.
+   * Should be called when the service is no longer needed.
+   * Complies with ADR-0003 (Observable Data Services) requirements.
+   */
+  destroy(): void {
+    this._destroy$.next();
+    this._destroy$.complete();
+  }
 }