fix: adjust multiline string formatting in resource generation

[battlebyte]

Adjusted multiline string formatting in terraform resource generation. Make sure <<EOF and EOF are correctly placed.
Expanded current testing to verify multiline strings.
Fixes https://konghq.atlassian.net/browse/FTI-6414.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 29.43%. Comparing base (f73569d) to head (004b2cb).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1482   +/-   ##
=======================================
  Coverage   29.43%   29.43%           
=======================================
  Files          61       61           
  Lines        6537     6537           
=======================================
  Hits         1924     1924           
  Misses       4474     4474           
  Partials      139      139           

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