[explorer] Update datatables packages

Summary:
Seeing an annoying error (sometimes) on page load, from datatables.

datatables is a cdn-delivered package. The version being used in explorer is pretty old.

Use the latest version.

ref: https://cdn.datatables.net/

Test Plan: cargo run and stuff seems to still work

Reviewers: #bitcoin_abc, roqqit

Reviewed By: roqqit

Differential Revision: https://reviews.bitcoinabc.org/D16628