[17.0][MIG] currency_rate_update_wise

[klodr]

currency_rate_update_wise → 17.0

Forward-port of the Wise.com exchange-rate provider from 14.0 to 17.0.
Framework migration only, no functional change.

Notes for reviewers

• Hermetic tests: the Wise HTTP layer (_wise_provider_retrieve) is mocked —
  no network access needed in CI.
• Carries a small, non-blocking helper that logs a warning when the configured
  API token still uses the legacy UUID format (Wise UUID → JWT migration).

[klodr]

A note on the red CI, for reviewers:

The only failing checks are test with OCB / test with Odoo, and they fail solely on the pre-existing currency_rate_update_xe module — its test_cron / test_wizard make real network calls to xe.com (which no longer returns usable data), so they assert 0 != 1. This is unrelated to this PR.

currency_rate_update_wise itself installs cleanly and all 10 of its tests pass — the Wise HTTP layer is mocked, so no network access is needed in CI. The xe.com test issue is already addressed for 17.0 in #218 (and #216 for 16.0, #220 for 14.0).