world_bank_wealth_account fails with an SSL certificate error #1291

Describe the bug
world_bank_wealth_account fails with an SSL certificate error when attempting to download wealth accounting data from the World Bank. The previous download endpoint (databank.worldbank.org) has an expired SSL certificate and is no longer the correct entry point for this dataset.

To Reproduce
Steps to reproduce the behaviour/error:

Note: You need to clear/backup the cached Wealth-Accounts_CSV to notice the error.

from climada.util.finance import world_bank_wealth_account
world_bank_wealth_account("CHE", 2010)

Expected behavior
Wealth accounting data for the requested country and year is returned without error.

Additional context
The World Bank has migrated the Wealth Accounts dataset to their Data Catalog (datacatalog.worldbank.org). The data is now accessible via the standard World Bank Indicators API at https://api.worldbank.org/v2/, which is the same API already used elsewhere in climada.util.finance. The zip+CSV download workflow can be replaced entirely by calls to the existing download_world_bank_indicator helper.