[Plugin] Wrap callback arguments for custom game actions in event arguments object, fix issue with unloading multiplayer plugins

[Basssiiie]

Hey all,

Hereby a PR that fixes some issues with custom actions in plugins in multiplayer.

• Implemented the breaking change regarding the callback arguments, as discussed in the #plugin channel in Discord.
• Fixed an issue where if a user descyncs from a multiplayer server, any remote plugins from that server would not unload properly.
  • This would break plugins with custom actions when the game tries to load the plugin in a new park, because the custom actions from the previous plugin load were still registered even though the plugin itself was not active anymore.
• Updated documentation regarding this breaking change and the previous G2 breaking change from Fix #18665, #18559: Add API for getting g2 icons by name #18675.
• Incremented plugin version to 69 (hehe nice) and network version to 2.

Some further issues I noticed but did not resolve here (may need to make issues for them):

• After a desync, remote plugins that are installed locally do not load into the current map.
• GameActionResult.error has the same issues as the G2 sprite enum had, in that it is referring to an unnumbered enum class that may be reordered at any time. This could break any plugin using this the next time this enum is updated.
  • Also if you do not specify an enum number (but you do specify a errorTitle and/or errorMessage), it will fallback to Ok and your error will be ignored.

Thank you for your time.

[Basssiiie]

Forgot to add one previously, but here's a sample plugin to help test the changes:

registerPlugin({
	name: 'Test custom action',
	version: '1',
	authors: ['Basssiiie'],
	type: 'remote',
	licence: 'MIT',
	targetApiVersion: 69,
	main() {
		context.registerAction("testaction",
			function(args)
			{
				// should include player/network info now
				console.log("Query action: " + JSON.stringify(args)); 
				return {};
			},
			function(args)
			{
				// should include player/network info now
				console.log("Execute action: " + JSON.stringify(args)); 
				return {};
			}
		);
		context.subscribe("action.execute", function(args)
		{
			// already included player/network info
			console.log("Action has executed: " + JSON.stringify(args));
		});
		ui.registerMenuItem("Execute test action", function()
		{
			context.executeAction("testaction", { value: "testarg" }, function(args)
			{
				// final cost result
				console.log("Finished executing action: " + JSON.stringify(args)); 
			});
		});
	},
});

[Basssiiie]

@IntelOrca would you be available by any chance for a review by any chance? Thanks. :)

[IntelOrca]

Is @Sadret now happy with these changes?

[Sadret]

Yes, it looks good to me.

[Basssiiie]

@IntelOrca are there any further changes you'd wish to request, by any chance? Or would it be looking good? Thanks :)