convert audit buttons to links

src/app/dars/dars-audit-view/dars-audit-view.component.html

 <div id="audit-view">
   <div class="audit-header-buttons">
-    <button id="audit-close" mat-button aria-label="Return to DARS audit list" color="primary" (click)="closeAudit()">
-      <mat-icon>chevron_left</mat-icon>
-      Return to audit list
-    </button>
-    <button id="audit-open-window" mat-button aria-label="Open audit in new tab" color="primary" (click)="openNewTab()">
-      Open in new tab
-      <mat-icon>launch</mat-icon>
-    </button>
+    <a
+      id="audit-close"
+      class="mat-button mat-primary"
+      routerLink="/dars"
+      aria-label="Return to DARS audit list">
+      <span class="mat-button-wrapper">
+        <mat-icon>chevron_left</mat-icon>
+        Return to audit list
+      </span>
+    </a>
+    <a
+      id="audit-open-window"
+      class="mat-button mat-primary"
+      target="_blank"
+      [routerLink]="['/dars', darsDegreeAuditReportId$ | async]"
+      aria-label="Open audit in new tab">
+      <span class="mat-button-wrapper">
+        Open in new tab
+        <mat-icon>launch</mat-icon>
+      </span>
+    </a>
   </div>
 
   <div class="audit-wrapper" *ngIf="audit$ | async as audit">