[release-2.1] Fix the problem of slug name with percent sign when publishing post (#3183)

This is an automated cherry-pick of #3179

/assign ruibaby

```release-note
修复因别名包含百分号导致无法正常访问的问题
```

src/main/java/run/halo/app/theme/router/RadixRouterTree.java

@@ -31,9 +31,7 @@ public class RadixRouterTree extends RadixTree<HandlerFunction<ServerResponse>>
     @Override
     public void insert(String key, HandlerFunction<ServerResponse> value)
         throws IllegalArgumentException {
-        // uri decode key to insert
+        super.insert(key, value);
-        String decodedKey = UriUtils.decode(key, StandardCharsets.UTF_8);
-        super.insert(decodedKey, value);
         if (log.isDebugEnabled()) {
             checkIndices();
         }

src/test/java/run/halo/app/theme/router/RadixRouterTreeTest.java

@@ -7,6 +7,7 @@ import java.net.URISyntaxException;
 import org.junit.jupiter.api.Test;
 import org.springframework.http.HttpMethod;
 import org.springframework.mock.web.reactive.function.server.MockServerRequest;
+import org.springframework.web.reactive.function.server.ServerResponse;
 
 /**
  * Tests for {@link RadixRouterTree}.
@@ -41,4 +42,10 @@ class RadixRouterTreeTest {
             .method(HttpMethod.GET).build();
         assertThat(RadixRouterTree.pathToFind(request)).isEqualTo("/?p=fake-post");
     }
+
+    @Test
+    void shouldInsertKeyWithPercentSign() {
+        var tree = new RadixRouterTree();
+        tree.insert("/1%1", request -> ServerResponse.ok().build());
+    }
 }