Merge branch 'fix-relative-submodule-namespace-path' into 'master'

Fix Error 500 when relative submodule resolves to a namespace that has a different name from its path

### What does this MR do?

This MR fixes a bug in resolving a namespace when the `name` differed from `path`.

### Why was this MR needed?

The original code was using `name`, when the proper input to `namespace_project_path` was `path`.

### What are the relevant issue numbers?

Closes #1849

See merge request !864