fix: accept non int stats values

[allisonsuarez]

Summary of Changes

Changed logic so non numerical stats values will not be converted to int.
amundsen-io/amundsen#778

Tests

test cases where stats values are dates.

Documentation

N/A

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[Golodhros]

Yay! Test Data Builders!

[Golodhros]

LGTM

Thanks for taking the time to add those tests!