gRPC import directory doesn't work as expected

### Is there an existing issue for this?

- [X] I have searched the [issue tracker](https://www.github.com/Kong/insomnia/issues) for a bug that matches the one I want to file, without success.

### Insomnia Version

2021.5.3

### What operating system are you using?

macOS

### Operating System Version

macOS Big Sur 11.6

### Installation method

homebrew

### Last Known Working Insomnia version

2021.5.3

### Expected Behavior

Let's consider this proto hierarchy:

```
protos/
common/
common.proto
microservicea/
common.proto (include common/common.proto)
a.proto (include common.proto)
microserviceb/
common.proto (include common/common.proto)
b.proto (include common.proto)
```

I would like to be able to import my protos without issues.

### Actual Behavior

Currently, when you Add Directory, in my case `protos`, it adds all proto files recursively. This is not what I expect / would like as it leads to a behaviour I can't fix as `a.proto` will be loaded, trying to include `common.proto`, except `protos/microservicea` was not added to import directory. It fails.

In Go and TS, we generate protos for each micro service including:
- root directory path (aka `protos`) , but it doesn't import recursively protos
- micro service path (aka `protos/microservicea`)

### Reproduction Steps

See description in Expected behaviour to reproduce the issue.

### Additional Information

Maybe a "Add Import Directory" (adding include path without importing protos) could solve the issue