Fix commit file status parser (go-gitea#30602)

Try to fix  go-gitea#30492

modules/git/commit.go

@@ -459,7 +459,7 @@ func parseCommitFileStatus(fileStatus *CommitFileStatus, stdout io.Reader) {
 		_, _ = rd.Discard(1)
 	}
 	for {
-		modifier, err := rd.ReadSlice('\x00')
+		modifier, err := rd.ReadString('\x00')
 		if err != nil {
 			if err != io.EOF {
 				log.Error("Unexpected error whilst reading from git log --name-status. Error: %v", err)