fix(android): append missing new lines on injected cordova files (#4058)

android/capacitor/src/main/java/com/getcapacitor/FileUtils.java

@@ -149,7 +149,7 @@ static String readFile(AssetManager assetManager, String fileName) throws IOExce
             StringBuffer buffer = new StringBuffer();
             String line;
             while ((line = reader.readLine()) != null) {
-                buffer.append(line);
+                buffer.append(line + "\n");
             }
 
             return buffer.toString();