Add Dart API for speech enhancement GTCRN models (#1993)

dart-api-examples/speech-enhancement-gtcrn/run.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+
+set -ex
+
+dart pub get
+
+if [ ! -f ./gtcrn_simple.onnx ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/speech-enhancement-models/gtcrn_simple.onnx
+fi
+
+if [ ! -f ./inp_16k.wav ]; then
+  curl -SL -O https://github.com/k2-fsa/sherpa-onnx/releases/download/speech-enhancement-models/inp_16k.wav
+fi
+
+
+dart run \
+  ./bin/speech_enhancement_gtcrn.dart \
+  --model ./gtcrn_simple.onnx \
+  --input-wav ./inp_16k.wav \
+  --output-wav ./enhanced-16k.wav
+
+ls -lh *.wav