Fix terraform init error with service-discovery alias providers

1.15.8 (July 8, 2026)

BUG FIXES:

• Fix terraform init error when installing providers sourced from a service-discovery alias advertised by the configured backend (such as localterraform.com)

NOTES:

• command/init: Provider installation was changed to enable future enhancements in the area. This effectively reverses the log message changes from v1.15. initializing_provider_plugin_message is being re-introduced to replace the short-lived two message types initializing_provider_plugin_from_config_message & initializing_provider_plugin_from_state_message. The change should not have any significant end-user impact aside from the command output. (#38838)

• command/init: Provider installation was changed to enable future enhancements in the area. This partially reverses the init event order changes from v1.15; module installation will now occur after the backend is initialized. The change should not have any significant end-user impact aside from the command output. (#38838)