Add onClientElementClicked for client side

[Xenius97]

Summary

onClientElementClicked event is now available on the client side, whereas previously it was only on server side (onElementClicked).

Motivation

During development, I often missed having this functionality on the client side, as I actively use it on the server as well. It provides a much simpler way to detect clicks on specific elements compared to manually handling it within onClientClick.
In my opinion, it can also be quite useful from a script optimization perspective.

Test plan

Click on a ped

-- create ped
local ped = createPed(0, 0, 0, 3)

-- new method
addEventHandler("onClientElementClicked", ped, function(button, state, worldX, worldY, worldZ)
    if button ~= "left" or state ~= "down" then return end
    outputChatBox("Ped clicked: " .. tostring(button) .. ", " .. tostring(state) .. ", " .. tostring(worldX) .. ", " .. tostring(worldY) .. ", " .. tostring(worldZ) .. ", Ped ID: " .. tostring(source) .. "(new method).")
end)

-- old method
-- addEventHandler("onClientClick", root, function(button, state, absoluteX, absoluteY, worldX, worldY, worldZ, clickedElement)
--     if button ~= "left" or state ~= "down" then return end
--     if clickedElement and clickedElement == ped then
--         outputChatBox("Ped clicked: " .. tostring(button) .. ", " .. tostring(state) .. ", " .. tostring(worldX) .. ", " .. tostring(worldY) .. ", " .. tostring(worldZ) .. ", Ped ID: " .. tostring(clickedElement) .. "(old method).")
--     end
-- end)

-- multiple peds
for i = 1, 5 do
    local ped = createPed(0, i * 2, 0, 3)
    addEventHandler("onClientElementClicked", ped, function(button, state, worldX, worldY, worldZ)
        if button ~= "left" or state ~= "down" then return end
        outputChatBox("Ped clicked: " .. tostring(button) .. ", " .. tostring(state) .. ", " .. tostring(worldX) .. ", " .. tostring(worldY) .. ", " .. tostring(worldZ) .. ", Ped ID: " .. tostring(source) .. "(new method).")
    end)
end

Checklist

• Your code should follow the coding guidelines.
• Smaller pull requests are easier to review. If your pull request is beefy, your pull request should be reviewable commit-by-commit.

[FileEX]

Adding this event is unnecessary duplication of events - we would be firing this event alongside onClientClick, which already includes the clicked element as an argument. On the server side, this event exists only because there is no onClick event there. Imo, adding a note on the onElementClicked wiki page stating that the client-side equivalent is onClientClick would be sufficient.

[Xenius97]

On the server side, this event exists only because there is no onClick event there.

https://wiki.multitheftauto.com/wiki/OnPlayerClick