fix 录音权限拒绝后录音crash

BFRecordScreenKit/Classes/RecordScreen/Controller/BFRecordScreenController.swift

@@ -969,6 +969,9 @@ public class BFRecordScreenController: BFBaseViewController {
     @objc func endRecord() {
         pause()
         // 存储录音
+        if !isRecording {
+            return
+        }
         isRecording = false
         progressThumV.progressView.isUserInteractionEnabled = true
         collectionView.isScrollEnabled = true