Fix the tab button to show correct tab name

[mokun]

Describe the bug
-When clicking on the arrow head tab button on left-bottom of a Unit Window, a pop is supposed to show the names of all tabs.

• Currently, the popup doesn't show the correct names.
• Instead, it shows e.g. 18. Tab.

Expected and unexpected behavior

• It is supposed to show the correct name in the popup

Java classes involved

• JTabbedPane, TabPanel, UnitWindow
• In addTabIconPanels() in UnitWindow, we have the following:

	/**
	 * Adds tab panels with icons.
	 */
	protected void addTabIconPanels() {
		tabPanels.forEach(panel -> {
			// Note: if adding panel.getTabTitle() as the first param, it would take up 
			// too much space on the left for displaying the name of each tab
			tabPane.addTab(null, panel.getTabIcon(), panel, panel.getTabToolTip());
		});
	}

Screenshots

Specifications

• pre 3.7.0 build 9075

Additional context

• This would have applied to all types of Unit Window but only SettlementUnitWindow is affected since it has so many tabs that when they stack up, they exceed the height of the unit window.
• Q: Should we overwrite JTabbedPane to get our desired UI appearance ? Or go back to simply use a library (e.g. jide-oss) out there that has new custom features for tabs ?

[mokun]

@bevans2000

Have you noticed this bug ?

[bevans2000]

We should not use a different library. This is not a massive problem.