fix: replace if statement with rxjs filtering

frontend/src/app/projects/project-detail/model-overview/model-overview.component.ts

@@ -6,7 +6,7 @@
 import { Component, OnInit } from '@angular/core';
 import { MatDialog } from '@angular/material/dialog';
 import { UntilDestroy, untilDestroyed } from '@ngneat/until-destroy';
-import { first } from 'rxjs';
+import { first, filter } from 'rxjs';
 import { ModelDiagramDialogComponent } from 'src/app/projects/models/diagrams/model-diagram-dialog/model-diagram-dialog.component';
 import {
   getPrimaryGitModel,
@@ -45,17 +45,16 @@ export class ModelOverviewComponent implements OnInit {
       .pipe(untilDestroyed(this))
       .subscribe((project) => (this.project = project));
 
-    this.modelService.models$.pipe(untilDestroyed(this)).subscribe((models) => {
-      if (models) {
+    this.modelService.models$
+      .pipe(untilDestroyed(this), filter(Boolean))
+      .subscribe((models) => {
         this.models = models.sort((a, b) => {
           if (a.display_order && b.display_order) {
             return a.display_order - b.display_order;
-          } else {
-            return b.id - a.id;
           }
+          return b.id - a.id;
         });
-      }
-    });
+      });
   }
 
   getPrimaryWorkingMode(model: Model): string {