refactor(OcrService): 移除重复的OcrHandler类型定义

已在@types中定义OcrHandler类型，移除重复定义以提高代码一致性

src/main/services/ocr/OcrService.ts

@@ -1,10 +1,8 @@
 import { loggerService } from '@logger'
-import { BuiltinOcrProviderIds, OcrProvider, OcrResult, SupportedOcrFile } from '@types'
+import { BuiltinOcrProviderIds, OcrHandler, OcrProvider, OcrResult, SupportedOcrFile } from '@types'
 
 import { tesseractService } from './tesseract/TesseractService'
 
-type OcrHandler = (file: SupportedOcrFile) => Promise<OcrResult>
-
 const logger = loggerService.withContext('OcrService')
 
 export class OcrService {