Tests

Added `files_upload_external` #1349

Job	Run time
test (ruby=2.7)	37s
test (ruby=2.7, concurrency=async-websocket)	39s
test (ruby=3.0)	19s
test (ruby=3.1)	24s
test (ruby=3.2)	21s
test (ruby=3.3)	26s
test (ruby=ruby-head)	19s
test (ruby=jruby-head)	1m 54s
coveralls	2s
	5m 1s

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