GHPerson#getType() should call populate() only if type is null

[anujhydrabadi]

Description

While calling the app or app installations endpoints, type is returned in the response from GitHub for users and organizations. Do not call populate() if type is already set. Perhaps we can fix this at the design level to prevent these kinds of bugs (caused because we do not know what fields have been populated already) from occurring altogether, but making a quick fix for this in the meantime.
Fixes #1816

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.57%. Comparing base (e14ec3b) to head (7201986).
Report is 6 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #2015      +/-   ##
============================================
- Coverage     83.61%   83.57%   -0.04%     
+ Complexity     2381     2380       -1     
============================================
  Files           235      235              
  Lines          7258     7259       +1     
  Branches        382      382              
============================================
- Hits           6069     6067       -2     
- Misses          955      956       +1     
- Partials        234      236       +2     

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[anujhydrabadi]

Please review. The codecov check is failing as it expects me to test the following code block too, which I feel will not be required. Please let me know if I need to add anything here.

if (isOffline()) {
            return; // cannot populate, will have to live with what we have
        }

Thanks!

[bitwiseman]

That code coverage hole is odd, but obviously not due to this change.