Can't set environment variable in interactive

### Description
**Outline the issue here:**
In the shell environment variables can't be set
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### Environment summary

**Install Method:** How did you install the CLI? (e.g. pip, interactive script, apt-get, Docker, MSI, nightly)
Answer here:

**CLI Version:** What version of the CLI and modules are installed? (Use `az --version`)
Answer here:

**OS Version:** What OS and version are you using?
Answer here:

**Shell Type:** What shell are you using? (e.g. bash, cmd.exe, Bash on Windows)
Answer here: