Output providers for troubleshooting

#2256 v1.15.2

Sometimes the output of terraform providers (or tofu providers) is useful to look into provider's version constraint.

In that case, you can see it in the log of setup action.

e.g.

Run "$TF" providers

Providers required by configuration:
.
└── provider[registry.terraform.io/hashicorp/null] 3.2.3