fix: plugin startup failed issue on Windows system (#3925)

#### What type of PR is this?
/kind bug
/area core
/milestone 2.6.x

#### What this PR does / why we need it:
修复在 Windows 系统无法启动插件的问题

how to test it?
1. 使用 windows 系统环境测试插件开发模式和生产模式是否正常工作
2. 测试从 2.0.0 版本安装插件然后切换到此 PR 后插件不会出现找不到文件的错误
3. 测试插件安装和升级是否正常

#### Which issue(s) this PR fixes:
Fixes #3906

#### Does this PR introduce a user-facing change?
```release-note
修复在 Windows 系统无法启动插件的问题
```

application/src/main/java/run/halo/app/core/extension/reconciler/PluginReconciler.java

@@ -577,7 +577,6 @@ public class PluginReconciler implements Reconciler<Request> {
         return pluginPath.toString();
     }
 
-
     /**
      * Returns absolute plugin path.
      * if plugin path is absolute, use it directly in development mode.
@@ -629,7 +628,11 @@ public class PluginReconciler implements Reconciler<Request> {
         if (StringUtils.isBlank(pathString)) {
             return null;
         }
-        return Paths.get(URI.create(pathString).getPath());
+        String processedPathString = pathString;
+        if (processedPathString.startsWith("file:")) {
+            processedPathString = processedPathString.substring(7);
+        }
+        return Paths.get(processedPathString);
     }
 
     URI toUri(String pathString) {

application/src/test/java/run/halo/app/core/extension/reconciler/PluginReconcilerTest.java

@@ -468,6 +468,14 @@ class PluginReconcilerTest {
             Path path = pluginReconciler.toPath("file:///path/to/file.txt");
             assertThat(path).isNotNull();
             assertThat(path.toString()).isEqualTo("/path/to/file.txt");
+
+            assertThat(pluginReconciler.toPath("C:\\Users\\faker\\halo\\plugins").toString())
+                .isEqualTo("C:\\Users\\faker\\halo\\plugins");
+            assertThat(pluginReconciler.toPath("C:/Users/faker/halo/plugins").toString())
+                .isEqualTo("C:/Users/faker/halo/plugins");
+            Path windowsPath = Paths.get("C:/Users/username/Documents/file.txt");
+            assertThat(pluginReconciler.toPath("file://C:/Users/username/Documents/file.txt"))
+                .isEqualTo(windowsPath);
         }
 
         @Test