fix(cli): passthru cli empty string args (#7301)

Close #771

---

### Changes are visible to end-users: yes

- Searched for relevant documentation and updated as needed: yes
- Breaking change (forces users to change their own code or config): no
- Suggested release notes appear below: yes

Fix the use of cli empty-string arguments.

### Test plan

- Manual testing; please provide instructions so we can reproduce:
passed `""` to various CLI commands and verified it gets passed into the
command code

GitOrigin-RevId: 08aa6c34918dd9858a4124e77274fd816745c0cd

Author: jbedard

pkg/aspect/root/flags/interceptor.go

@@ -60,6 +60,7 @@ func FlagsInterceptor(streams ioutils.Streams) interceptors.Interceptor {
 			doubleDash := false
 			for _, arg := range args {
 				if arg == "" {
+					forwardArgs = append(forwardArgs, arg)
 					continue
 				}
 				if arg == "--" {