[TIMOB-28570] Android: Add "homeAsUpIndicator" custom icon support to ActionBar

*Summary:* Titanium does not offer an API to set the home indicator to a custom icon on the ActionBar. This means it's currently limited to a back arrow or the hamburger icon. Ideally, we should add support for a custom icon such as a \[x\] button. *To-Do:* Add property "homeAsUpIndicator" property to Ti.Android.ActionBar. Have it call the Java [ActionBar.setHomeAsUpIndicator()](https://developer.android.com/reference/android/app/ActionBar#setHomeAsUpIndicator(int)) method. This property should support drawable resource ID (such as a vector drawable) or an image string path. *Test:*

Use below code as the "app.js".

Create folder: ./platform/android/res/drawable

Copy [^ic_baseline_close_24.xml] to above directory.

Build and run on Android.

Verify you see a close \[x\] button in top-left corner of action bar.

const window = Ti.UI.createWindow();
window.activity.onCreate = () => {
	const actionBar = window.activity.actionBar;
	actionBar.displayHomeAsUp = true;
	actionBar.homeButtonEnabled = true;
	actionBar.homeAsUpIndicator = Ti.App.Android.R.drawable.ic_baseline_close_24;
	actionBar.onHomeIconItemSelected = () => {
		alert("Clicked on ActionBar home icon.");
	};
};
window.open();

*Work-Around:* Use Titanium's Toolbar instead via its [navigationIcon](https://titaniumsdk.com/api/titanium/ui/toolbar.html#navigationicon) property. This is the equivalent of the ActionBar's home indicator, but takes more effort to implement.