fix: klaviyo bulk upload and BingAds OC

[yashasvibajpai]

Description

add fixes for

• Klaviyo Bulk Upload
• BingAds Offiine conversions integrations

Linear Ticket

Resolves INT-2820 INT-2916

Security

• The code changed/added as part of this pull request won't create any security issues with how the software is being used.

[codecov]

Codecov Report

Attention: Patch coverage is 36.55172% with 92 lines in your changes missing coverage. Please review.

Project coverage is 73.47%. Comparing base (94aa254) to head (08f4af1).
Report is 1 commits behind head on release/1.38.x.

Files with missing lines	Patch %	Lines
...destinationmanager/klaviyobulkupload/apiService.go	12.76%	82 Missing ⚠️
...tionmanager/klaviyobulkupload/klaviyobulkupload.go	80.00%	8 Missing and 2 partials ⚠️

Additional details and impacted files

@@                Coverage Diff                 @@
##           release/1.38.x    #5305      +/-   ##
==================================================
+ Coverage           73.40%   73.47%   +0.07%     
==================================================
  Files                 424      425       +1     
  Lines               60243    59965     -278     
==================================================
- Hits                44221    44060     -161     
+ Misses              13578    13434     -144     
- Partials             2444     2471      +27     

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