Fix searching/filtering bugs #235

- Fix a bug (introduced in 1b9be8fe) preventing the tree view from being
  visible during a search.
- Fix a minor bug where the scripts view does not render based on the
  initial filter.
- Add Vue component tests for `TheScriptView` to prevent regressions.
- Refactor `isSearching` in `TheScriptView` to simplify its logic.

tests/unit/shared/Stubs/UseApplicationStub.ts

@@ -0,0 +1,19 @@
+import { useApplication } from '@/presentation/components/Shared/Hooks/UseApplication';
+import { IApplication } from '@/domain/IApplication';
+import { ApplicationStub } from './ApplicationStub';
+
+export class UseApplicationStub {
+  private application: IApplication = new ApplicationStub();
+
+  public withState(application: IApplication) {
+    this.application = application;
+    return this;
+  }
+
+  public get(): ReturnType<typeof useApplication> {
+    return {
+      application: this.application,
+      info: this.application.info,
+    };
+  }
+}