feat: add "isTrusted" property to Slider "change" event

[m1ga]

JIRA:
https://jira.appcelerator.org/browse/TIMOB-27977

Summary:
Added a "isTrusted" boolean property to Ti.UI.Slider object's "change" event. Property will be true if change came from the end-user. Will be false if change was made programmatically. This is a standard JavaScript event property available to web developers. (In the future, we should apply this property to all events.)
https://developer.mozilla.org/en-US/docs/Web/API/Event/isTrusted

Test:

1. Build and run the below for Android.
2. Drag the slider with your finger.
3. In the log, verify change event's isTrusted property is set to true.
4. Tap on the "Update Slider" button.
5. In the log, verify change event's isTrusted property is set to false.

var window = Ti.UI.createWindow();
var slider = Ti.UI.createSlider({
	min: 0.0,
	max: 1.0,
	value: 0.25,
});
slider.addEventListener("change", function(e) {
	Ti.API.info("@@@ slider value changed: " + e.value + ", isTrusted: " + e.isTrusted);
});
window.add(slider);
var button = Ti.UI.createButton({
	title: "Update Slider Position",
	bottom: "20dp",
});
button.addEventListener("click", function() {
	slider.value = 0.5;
});
window.add(button);
window.open();

[build]

	Fails
🚫	Tests have failed, see below for more information.

	Warnings
⚠️	Commit fae39e6a5cf54d88213ad7c3f0b9cf5c02358f65 has a message "change to isTrusted, docu" giving 2 errors: subject may not be empty type may not be empty

	Messages
📖	💾 Here's the generated SDK zipfile.
📖	🎉 Another contribution from our awesome community member, m1ga! Thanks again for helping us make Titanium SDK better. 👍
📖	🚨 This PR has one or more commits with warnings/errors for commit messages not matching our configuration. You may want to squash merge this PR and edit the message to match our conventions, or ask the original developer to modify their history.
📖	❌ 2 tests have failed There are 2 tests failing and 698 skipped out of 7347 total tests.

Tests:

Classname	Name	Time	Error
android.emulator.Titanium.UI.TextArea	.focused (9)	2.297	Error: timeout of 2000ms exceeded at Titanium.<anonymous> (/ti-mocha.js:6535:53723)
android.emulator.Titanium.UI.TextField	.focused (9)	2.328	Error: timeout of 2000ms exceeded at Titanium.<anonymous> (/ti-mocha.js:6535:53723)

Generated by 🚫 dangerJS against cd85cfd

[jquick-axway]

@m1ga, would you mind if I add changes to this PR?
I'd like to make the same change to iOS and add a unit test.

[m1ga]

@jquick-axway no, go ahead!

[jquick-axway]

PR updated:

• Added property to iOS for parity.
• Added unit test.
• Updated API docs.

@janvennemann, would you mind reviewing the iOS side? Do you have any objections to this new event property?

[janvennemann]

@jquick-axway iOS change looks good. I'm fine with introducing this now since we already fire the event on programmatic changes. Eventually we should stop firing the change event after programmatic changes though, but as already discussed we can deal with that in a separate ticket for an upcoming major release.

[ssjsamir]

FR Passed Tested using the test case and instructions mentioned above in the description.

Test Environment

MacOS Big Sur: 11.0 Beta
Xcode: 12.0 Beta 
Java Version: 1.8.0_242
Android NDK: 21.3.6528147
Node.js: 12.18.1
""NPM":"5.0.0","CLI":"8.0.0""
iphone 8 Sim (14.0 Beta)
API29 Pixel XL emulator

[ssaddique]

Fix verified on build 9.1.0.v20200804082025.

Test environment

OS Ver:         10.15.3
Xcode Ver:      Xcode 11.6
Appc NPM:       5.0.0
Appc CLI:       8.0.0
Node Ver:       10.17.0
Java Ver:       1.8.0_162
Devices:        iPhone 6 (12.1.4), Pixel 3a (11.0)

I must note that when clicking the 'Update' button, the value is logged twice:

[INFO] @@@ slider value changed: 0.5, isTrusted: false
[INFO] @@@ slider value changed: 0.5, isTrusted: false