command/import: fix error during import when implied provider was not used (#22855)

* command/import: properly use `-provider` supplied on the command line

The import command now attaches the provider configuration in the resource
instance, if set. That config is attached to the NodeAbstractResource
during the import graph building. This prevents errors when the implied
provider is not actually in the configuration at all, which may happen
when a configuration is using the `-beta` version of a provider (and
only that `-beta` version).

* command/import: fix variable reassignment and update docs

Fixes #22564

Author: mildwonkey

terraform/graph_builder_import.go

@@ -55,6 +55,9 @@ func (b *ImportGraphBuilder) Steps() []GraphTransformer {
 		// Create all our resources from the configuration and state
 		&ConfigTransformer{Config: config},
 
+		// Attach the configuration to any resources
+		&AttachResourceConfigTransformer{Config: b.Config},
+
 		// Add the import steps
 		&ImportStateTransformer{Targets: b.ImportTargets},