Description of problem:

If the extension fails to download the Analyzer RPC binary, a generic error message is displayed when trying to use the extension: TypeError: fetch failed

Version-Release number of selected component (if applicable):

8.0.3 of the IDE extension.

How reproducible:

Always

Steps to Reproduce:

1. Install the extension in a network restricted environment that can't access the binary published in developer.redhat.com
2. Installation finishes successfully.
3. Activate the extension (e.g. ctrl-shift-P and an MTA command),

Actual results:

Generic error message: TypeError: fetch failed

Expected results:

Either installation fails, or a more explanatory error message: "Failed to fecth the analyzer RPC binary, see documentation for offline setup"