fix: template rendering missing template_id model data (#3414)

#### What type of PR is this?
/kind bug
/area core
/milestone 2.3.x

#### What this PR does / why we need it:
修复文章模板渲染丢失 template_id 参数导致无法代码注入的问题

how to test it?
测试 [plugin-highlightjs](https://github.com/halo-sigs/plugin-highlightjs) 插件功能是否正常，期望在 html head 插入 `/plugins/PluginHighlightJS/assets/static/highlight.min.js`

#### Which issue(s) this PR fixes:
Fixes #3403

#### Does this PR introduce a user-facing change?
```release-note
None
```

src/main/java/run/halo/app/theme/router/factories/PostRouteFactory.java

@@ -102,6 +102,7 @@ public class PostRouteFactory implements RouteFactory {
         return postVoMono
             .flatMap(postVo -> {
                 Map<String, Object> model = new HashMap<>();
+                model.put(ModelConst.TEMPLATE_ID, DefaultTemplateEnum.POST.getValue());
                 model.put("groupVersionKind", GroupVersionKind.fromExtension(Post.class));
                 GVK gvk = Post.class.getAnnotation(GVK.class);
                 model.put("plural", gvk.plural());

src/test/java/run/halo/app/theme/router/factories/PostRouteFactoryTest.java

@@ -0,0 +1,90 @@
+package run.halo.app.theme.router.factories;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.when;
+
+import java.util.Map;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.http.MediaType;
+import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.web.reactive.function.server.RouterFunction;
+import org.springframework.web.reactive.function.server.ServerResponse;
+import org.springframework.web.server.ServerWebExchange;
+import reactor.core.publisher.Mono;
+import run.halo.app.content.TestPost;
+import run.halo.app.core.extension.content.Post;
+import run.halo.app.extension.ExtensionUtil;
+import run.halo.app.extension.GroupVersionKind;
+import run.halo.app.extension.ReactiveExtensionClient;
+import run.halo.app.theme.DefaultTemplateEnum;
+import run.halo.app.theme.finders.PostFinder;
+import run.halo.app.theme.finders.vo.PostVo;
+import run.halo.app.theme.router.EmptyView;
+import run.halo.app.theme.router.ViewNameResolver;
+
+/**
+ * Tests for {@link PostRouteFactory}.
+ *
+ * @author guqing
+ * @since 2.3.0
+ */
+@ExtendWith(MockitoExtension.class)
+class PostRouteFactoryTest extends RouteFactoryTestSuite {
+
+    @Mock
+    private PostFinder postFinder;
+
+    @Mock
+    private ViewNameResolver viewNameResolver;
+
+    @Mock
+    private ReactiveExtensionClient client;
+
+    @InjectMocks
+    private PostRouteFactory postRouteFactory;
+
+    @Test
+    void create() {
+        Post post = TestPost.postV1();
+        Map<String, String> labels = ExtensionUtil.nullSafeLabels(post);
+        labels.put(Post.PUBLISHED_LABEL, "true");
+        post.getMetadata().setName("fake-name");
+        post.getSpec().setDeleted(false);
+        post.getSpec().setVisible(Post.VisibleEnum.PUBLIC);
+        when(postFinder.getByName(eq("fake-name"))).thenReturn(Mono.just(PostVo.from(post)));
+
+        when(client.fetch(eq(Post.class), eq("fake-name"))).thenReturn(Mono.just(post));
+
+        when(viewNameResolver.resolveViewNameOrDefault(any(), any(), any()))
+            .thenReturn(Mono.just(DefaultTemplateEnum.POST.getValue()));
+
+        RouterFunction<ServerResponse> routerFunction = postRouteFactory.create("/archives/{name}");
+        WebTestClient webTestClient = getWebTestClient(routerFunction);
+
+        when(viewResolver.resolveViewName(any(), any()))
+            .thenReturn(Mono.just(new EmptyView() {
+                @Override
+                public Mono<Void> render(Map<String, ?> model, MediaType contentType,
+                    ServerWebExchange exchange) {
+                    assertThat(model).containsKey(ModelConst.TEMPLATE_ID);
+                    assertThat(model.get(ModelConst.TEMPLATE_ID))
+                        .isEqualTo(DefaultTemplateEnum.POST.getValue());
+                    assertThat(model.get("plural")).isEqualTo("posts");
+                    assertThat(model.get("post")).isNotNull();
+                    assertThat(model.get("groupVersionKind"))
+                        .isEqualTo(GroupVersionKind.fromExtension(Post.class));
+                    return super.render(model, contentType, exchange);
+                }
+            }));
+        webTestClient.get()
+            .uri("/archives/fake-name")
+            .exchange()
+            .expectStatus().isOk();
+    }
+}