Update ReactNative build.gradle to use new dev server port property

Author: nhunzaker

ReactAndroid/build.gradle

@@ -203,8 +203,8 @@ def findNdkBuildFullPath() {
     return null
 }
 
-def debugHostPort(String defaultValue){
-    def value = project.getProperties().get("debugHostPort")
+def reactNativeDevServerPort(String defaultValue) {
+    def value = project.getProperties().get("reactNativeDevServerPort")
     return value != null ? value : defaultValue
 }
 
@@ -295,7 +295,7 @@ android {
         buildConfigField("boolean", "IS_INTERNAL_BUILD", "false")
         buildConfigField("int", "EXOPACKAGE_FLAGS", "0")
 
-        resValue "integer", "react_native_dev_server_port", "8081"
+        resValue "integer", "react_native_dev_server_port", reactNativeDevServerPort("8081")
 
         testApplicationId("com.facebook.react.tests.gradle")
         testInstrumentationRunner("androidx.test.runner.AndroidJUnitRunner")