When the software starts from boot, cordova-plugin-file cannot mount sdcard correctly when initialized

# Bug Report

## Problem

### What is expected to happen?
When the software starts, it wants to read the file under the sdcard normally

### What does actually happen?

In fact, reading a file throws an ENCODING ERR error

## Information

Through debugging, I found that the sdcard was not mounted when the device was just booted and was mounted after the plugin was initialized

### Command or Code

In the case of unplugging the sdcard, start the software and reinsert the sdcard

### Environment, Platform, Device

Android 10 Device

### Version information
What are relevant versions you are using?
cordova-plugin-file 6.0.2

Start by reproducing the issue on an Android 10 device using the described boot, unplug, and reinsert sequence, then inspect the plugin initialization timing relative to sdcard mounting. Done means the software can read files normally when the sdcard mounts after startup, without an ENCODING ERR error.

Written by the indexing model from the issue text.