fix: allow ParseRole to save when using custom objectId's

[cbaker6]

New Pull Request Checklist

• I am not disclosing a vulnerability.
• I am creating this PR in reference to an issue.

Issue Description

When the SDK is allowing custom objectId's, new users and roles can't be saved to ParseRole's.

This occurs because a ParseRelation has a target of Pointer<ParseObject>. Since a Parse Pointer doesn't have createdAt, an error is being thrown.

Related issue: #n/a

Approach

Since an ParseOperation can occur on a ParseObject or a ParseRelation, only check if the objectId is present on the target.

TODOs before merging

• Add tests
• Add entry to changelog

[parse-github-assistant]

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• 🎉 We are excited about your hands-on contribution!

[codecov]

Codecov Report

Merging #338 (a1932a3) into main (aa02ed9) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #338      +/-   ##
==========================================
+ Coverage   85.10%   85.15%   +0.04%     
==========================================
  Files         114      114              
  Lines       12208    12208              
==========================================
+ Hits        10390    10396       +6     
+ Misses       1818     1812       -6     

Impacted Files	Coverage Δ
Sources/ParseSwift/Types/ParseOperation.swift	97.59% <100.00%> (+2.88%)	⬆️

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