Updated def build_personalization

[theanuraganand]

Corrected a typo.

Fixes

Checklist

• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the [Contribution Guide] and my PR follows them.
• I updated my branch with the master branch.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation about the functionality in the appropriate .md file
• I have added in line documentation to the code I modified

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[SendGridDX]

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[thinkingserious]

Hello @theanuraganand,

Thanks again for the PR!

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