fixing deviceIdentifier validation issue

components/mobile-plugins/android-plugin/org.wso2.carbon.device.mgt.mobile.android.api/src/main/java/org/wso2/carbon/mdm/services/android/bean/wrapper/AndroidDevice.java

@@ -53,7 +53,6 @@ public class AndroidDevice implements Serializable {
     )
     @NotNull
     @Size(min = 2, max = 45)
-    @Pattern(regexp = "^[A-Za-z0-9]*$")
     private String deviceIdentifier;
     @ApiModelProperty(
             name = "enrolmentInfo",