fix(ios): TableView "sectionCount" property crash

[jquick-axway]

JIRA:
https://jira.appcelerator.org/browse/TIMOB-13903

Unit Test Note:
RecylerView PR #12029 is making heavy changes to the ti.ui.tableview.test.js script. In order to avoid a huge amount of conflicts, we should re-enable all iosBroken unit tests via that PR instead of this one.
(I've already verified this PR's change fixes the unit tests.)

Test:

1. Build and run the below on iOS.
2. Verify an alert displays "sectionCount: 2" on app startup.

var section1 = Ti.UI.createTableViewSection({ headerTitle: "Colors" });
section1.add(Ti.UI.createTableViewRow({ title: "Red" }));
section1.add(Ti.UI.createTableViewRow({ title: "Green" }));
section1.add(Ti.UI.createTableViewRow({ title: "Blue" }));

var section2 = Ti.UI.createTableViewSection({ headerTitle: "Fruit" });
section2.add(Ti.UI.createTableViewRow({ title: "Apples" }));
section2.add(Ti.UI.createTableViewRow({ title: "Bananas" }));
section2.add(Ti.UI.createTableViewRow({ title: "Peaches" }));

var window = Ti.UI.createWindow();
var tableView = Ti.UI.createTableView({
	data: [section1, section2],
});
window.add(tableView);
window.addEventListener("open", function() {
	alert("sectionCount: " + tableView.sectionCount);
});
window.open();

[build]

	Messages
📖	💾 Here's the generated SDK zipfile.
📖	✊ The commits in this PR match our conventions! Feel free to Rebase and Merge this PR when ready.
📖	✅ All tests are passing Nice one! All 10091 tests are passing. (There are 975 skipped tests not included in that total)

Generated by 🚫 dangerJS against 5af24ef

[sgtcoolguy]

I think this is the only required change, and the rest of the lines/changes are not necessary. Why not just leave this method as returning NSUInteger as before and avoid the need to explicitly call [NSNumber unsignedIntegerValue] to get one in the above changes?

[jquick-axway]

It wasn't crashing because sections was nil.
(That's just a safety mechanism I added just in case.)

It was crashing because the calling code here expected the property's return type to be an NSObject derived type, but it received an NSUInteger which is a typedef'ed unsigned int. That's why I changed it to NSNumber, which is the same return type our TiUIListViewProxy uses for sectionCount here.

[ssaddique]

FR: Pass

Test Environment
SDK Ver: this PR
OS Ver: 10.15.6
Xcode Ver: Xcode 12.0.1
Appc NPM: 5.0.0
Appc CLI: 8.1.1
Ti CLI Ver: 5.2.5
Alloy Ver: 1.15.2
Node Ver: 10.19.0
NPM Ver: 6.13.6
Emulator: iPhone 8 (13.5), iPhone 11 Pro (14.0)