Tests

Update API from slack-api-ref@c408935 (2025-07-05) #1732

Job	Run time
test (ruby=2.7)	33s
test (ruby=2.7, concurrency=async-websocket)	35s
test (ruby=3.0)	25s
test (ruby=3.1)	21s
test (ruby=jruby-head)	2m 46s
test (ruby=3.3)	30s
test (ruby=ruby-head)	12s
test (ruby=3.2)	23s
test (ruby=3.4)	20s
coveralls	6s
	6m 11s

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