Avoid showing provider form if proivder is set up (#1128)

bitwarden_license/src/app/providers/setup/setup.component.ts

@@ -58,9 +58,21 @@ export class SetupComponent implements OnInit {
                 };
                 this.toasterService.popAsync(toast);
                 this.router.navigate(['/']);
-            } else {
+                return;
+            }
+
             this.providerId = qParams.providerId;
             this.token = qParams.token;
+            
+            // Check if provider exists, redirect if it does
+            try {
+                const provider = await this.apiService.getProvider(this.providerId);
+                if (provider.name != null) {
+                    this.router.navigate(['/providers', provider.id], { replaceUrl: true });
+                }
+            } catch (e) {
+                this.validationService.showError(e);
+                this.router.navigate(['/']);
             }
         });
     }