gRPC schema hangs on Inspecting Schema

I’m trying to load the schema for a gRPC service, and it goes “Inspecting Schema” and spins forever.

On the command line, there’s a single related line of output:
```
add file descriptor proto: entity/variant/v1/get_variant_request.proto: imported file 'entity/variant/v1/variant_id.proto' has not been added
```
Using the grpcurl tool, I can view the schema for these messages over reflection:

```

murph@realwork backend % grpcurl -plaintext localhost:8080 describe entity.variant.v1.VariantEntityService.GetVariant
entity.variant.v1.VariantEntityService.GetVariant is a method:
rpc GetVariant ( .entity.variant.v1.GetVariantRequest ) returns ( .entity.variant.v1.GetVariantResponse );
murph@realwork backend % grpcurl -plaintext localhost:8080 describe .entity.variant.v1.GetVariantRequest              
entity.variant.v1.GetVariantRequest is a message:
message GetVariantRequest {
 .entity.variant.v1.VariantId id = 1;
}
murph@realwork backend % grpcurl -plaintext localhost:8080 describe .entity.variant.v1.VariantId                      
entity.variant.v1.VariantId is a message:
message VariantId {
 string value = 1;
}
```