fix: correct file mime type validation parameter to restore functiona…

…lity (#6673)

#### What type of PR is this?
/kind bug
/area core
/milestone 2.20.x

#### What this PR does / why we need it:
修复文件上传时类型校验失效的问题

此问题由 #6390 导致

#### Does this PR introduce a user-facing change?
```release-note
修复文件上传时类型校验失效的问题
```

application/src/main/java/run/halo/app/core/attachment/endpoint/LocalAttachmentUploadHandler.java

@@ -6,6 +6,7 @@
 import static run.halo.app.infra.utils.FileUtils.deleteFileSilently;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.FileAlreadyExistsException;
@@ -25,6 +26,7 @@
 import org.springframework.core.io.buffer.DataBufferUtils;
 import org.springframework.http.MediaType;
 import org.springframework.http.codec.multipart.FilePart;
+import org.springframework.lang.NonNull;
 import org.springframework.stereotype.Component;
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.StringUtils;
@@ -156,19 +158,14 @@ private Mono<Void> validateFile(FilePart file, PolicySetting setting) {
             var typeValidator = file.content()
                 .next()
                 .handle((dataBuffer, sink) -> {
-                    var mimeType = "Unknown";
-                    try {
-                        mimeType = FileTypeDetectUtils.detectMimeType(dataBuffer.asInputStream());
-                        var isAllow = setting.getAllowedFileTypes()
-                            .stream()
-                            .map(FileCategoryMatcher::of)
-                            .anyMatch(matcher -> matcher.match(file.filename()));
-                        if (isAllow) {
-                            sink.next(dataBuffer);
-                            return;
-                        }
-                    } catch (IOException e) {
-                        log.warn("Failed to detect file type", e);
+                    var mimeType = detectMimeType(dataBuffer.asInputStream());
+                    var isAllow = setting.getAllowedFileTypes()
+                        .stream()
+                        .map(FileCategoryMatcher::of)
+                        .anyMatch(matcher -> matcher.match(mimeType));
+                    if (isAllow) {
+                        sink.next(dataBuffer);
+                        return;
                     }
                     sink.error(new FileTypeNotAllowedException("File type is not allowed",
                         "problemDetail.attachment.upload.fileTypeNotSupported",
@@ -180,6 +177,16 @@ private Mono<Void> validateFile(FilePart file, PolicySetting setting) {
         return Mono.when(validations);
     }
 
+    @NonNull
+    private String detectMimeType(InputStream inputStream) {
+        try {
+            return FileTypeDetectUtils.detectMimeType(inputStream);
+        } catch (IOException e) {
+            log.warn("Failed to detect file type", e);
+            return "Unknown";
+        }
+    }
+
     @Override
     public Mono<Attachment> delete(DeleteContext deleteContext) {
         return Mono.just(deleteContext)