docs: Add vision-camera-cropper to the plugins list (#2600)

docs/docs/guides/FRAME_PROCESSOR_PLUGINS.mdx

@@ -33,6 +33,7 @@ cd ios && pod install
 * [xulihang/**vision-camera-dynamsoft-barcode-reader**](https://github.com/xulihang/vision-camera-dynamsoft-barcode-reader): A plugin to read barcodes using Dynamsoft Barcode Reader.
 * [xulihang/**vision-camera-dynamsoft-label-recognizer**](https://github.com/xulihang/vision-camera-dynamsoft-label-recognizer): A plugin to recognize text on labels, MRZ passports, etc. using Dynamsoft Label Recognizer.
 * [tony-xlh/**vision-camera-dynamsoft-document-normalizer**](https://github.com/tony-xlh/vision-camera-dynamsoft-document-normalizer): A plugin to scan documents using Dynamsoft Document Normalizer with features like document border detection and perspective transformation.
+* [tony-xlh/**vision-camera-cropper**](https://github.com/tony-xlh/vision-camera-cropper): A plugin to crop frames and save frames to files or as base64.
 * [aarongrider/**vision-camera-ocr**](https://github.com/aarongrider/vision-camera-ocr): A plugin to detect text in real time using MLKit Text Detector (OCR).
 * [yasintorun/**vision-camera-base64**](https://github.com/yasintorun/vision-camera-base64): A plugin to convert a Frame to a base64 string.