use native onClick in place of clickHandler prop in custom buttons

[interim17]

Time estimate or Size

small

NavButton and ViewportButton use a custom prop of clickHandler which is essentially the same as the antd Button's native onClick

More symmetry in the props of different buttons (basic antd as well as our wrappers, and the <button> they eventually render in the DOM), is useful when managing focus and click/keyboard navigation behavior.

I don't recall a justification for using clickHandler instead of just onClick that I can remember so I'd like to switch them all to onClick.

[github-actions]

Coverage report

St.❔	Category	Percentage	Covered / Total
🟡	Statements	66.92%	696/1040
🟡	Branches	67.1%	104/155
🔴	Functions	35.5%	93/262
🟡	Lines	65.3%	619/948

Test suite run success

129 tests passing in 7 suites.

Report generated by 🧪jest coverage report action from df11ed3

[toloudis]

I don't know technically why onClick is better than clickHandler or whether there's any difference at all. Apart from that, if everything's working, I approve!

[interim17]

I don't know technically why onClick is better than clickHandler or whether there's any difference at all. Apart from that, if everything's working, I approve!

In previous code no practical difference, but if for example you want to inject functions or otherwise work with different types of buttons, and some of them have clickHandler and some don't it adds complexity. It's nice if their props are the same whenever possible.

Realizing this as I work on keyboard navigation and wanted to just get ahead of it.