feat: enhance cloud check in PostgresLoader to work in any GCP environment

[stdavis]

Prior to this change, it only worked in functions.

I didn't have a great way to test this but I'm fairly certain that it's good. I did test the False path and it worked.

[codecov]

Codecov Report

Attention: Patch coverage is 71.42857% with 2 lines in your changes missing coverage. Please review.

Project coverage is 94.64%. Comparing base (f87f4c5) to head (5f5f384).
Report is 38 commits behind head on main.

Files with missing lines	Patch %	Lines
src/palletjack/extract.py	0.00%	0 Missing and 1 partial ⚠️
src/palletjack/utils.py	83.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #111      +/-   ##
==========================================
+ Coverage   94.52%   94.64%   +0.11%     
==========================================
  Files           7        7              
  Lines        1133     1157      +24     
  Branches      148      177      +29     
==========================================
+ Hits         1071     1095      +24     
- Misses         52       53       +1     
+ Partials       10        9       -1     

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[jacobdadams]

Looks good to me. Thanks for the update.