Simplify cop rule Scalability/FileUploads

What does this MR do and why?

This MR simplifies 👮 rule Scalability/FileUploads by unifying 3 node patterns (2 static and one dynamic) into a single one which uses {} union and $ captures.

Found during investigation of !111008 (merged).

How to set up and validate locally

$ bundle exec rubocop  --only Scalability/FileUploads lib/api

Inspecting 541 files
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541 files inspected, no offenses detected

MR acceptance checklist

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