[fix] : add default linode URL

[rahulait]

General:

Newer versions of linodego added a fix where they error out early if host or scheme are not set. It doesn't automatically use a default value. linode/linodego#758

This PR fixes CCM where it was passing empty value if required var was not set and was then failing.
Fixes #424

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 72.45%. Comparing base (b0bf52f) to head (1b89f9a).
⚠️ Report is 16 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #425      +/-   ##
==========================================
+ Coverage   72.44%   72.45%   +0.01%     
==========================================
  Files          19       19              
  Lines        3498     3500       +2     
==========================================
+ Hits         2534     2536       +2     
  Misses        733      733              
  Partials      231      231              

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