@ionic-native/mobile-accessibility incorrectly references available methods

[kelvindart]

I'm submitting a ... (check one with "x")
[x] bug report
[ ] feature request
[ ] support request

Current behavior:
I am raising this issue to support a PR which I will reference after submitting this. Currently, the @ionic-native wrapper for the plugin phonegap-mobile-accessibility, incorrectly references a number of functions. This results in a plugin_not_installed error when attempting to reference these.

Expected behavior:
For the available methods on @ionic-native to be available, and for these to call the subsequent plugin methods. I have altered said , ran the test steps and verified they work.

Steps to reproduce:

1. Clone the following repository: https://github.com/kelvindart/ionic-mobile-accessibility
2. Run npm i
3. Emulate this on a device: ionic cordova emulate ios --target=iPhone-SE
4. Observe error.

Related code:
With @ionic-native/mobile-accessibility@4.4.2, the following code results in the plugin_not_installed error.

constructor(mobileAccessibility: MobileAccessibility) {
  this.platform.ready()
    .then(() => mobileAccessibility.getTextZoomCallback())
    .then(e => this.zoomLevel = e);
}

With the fix, the following bit of code correctly calls the subsequent method:

constructor(mobileAccessibility: MobileAccessibility) {
  this.platform.ready()
    .then(() => mobileAccessibility.getTextZoom())
    .then(e => this.zoomLevel = e);
}

Other information:
N/A

Ionic info:

cli packages: (/usr/local/lib/node_modules)

    @ionic/cli-utils  : 1.9.2
    ionic (Ionic CLI) : 3.9.2

global packages:

    Cordova CLI : 7.1.0 

local packages:

    @ionic/app-scripts : 3.1.0
    Cordova Platforms  : ios 4.5.3
    Ionic Framework    : ionic-angular 3.9.2

System:

    Android SDK Tools : 26.1.1
    ios-deploy        : 1.9.2 
    ios-sim           : 6.1.2 
    Node              : v9.2.0
    npm               : 5.5.1 
    OS                : macOS High Sierra
    Xcode             : Xcode 9.1 Build version 9B55