Update Copyright year to 2024

Summary:
In node and explorer

Similar to D12962 and D12974

Test Plan:
ninja
./src/bitcoind --version
./src/qt/bitcoin-qt --version
Run explorer locally and check copyright footer

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D15238