OpenAPI specs v240.7.3

OpenAPI specs from chat release v240.7.3.

• [CHA-6677] Count every channel and message write in stored-count gauges (PR: #20314, Author: @hifaizsk)
• [INF-2030] Move us-east4 c2 and c10 Valkey to shared pool b (PR: #20414, Author: @mogita)
• [FEEDS-2208] Inherit v2-migration limits when importing a migrated app's export (PR: #20342, Author: @dzoke)
• [CHA-6442] Write sync events to TiKV inside the task, with the DynamoDB guarantee (PR: #20388, Author: @slavabobik)
• [VID-1697] Run the v240.7.2 release on the staging-video VEP (PR: #20410, Author: @atoppi)
• [CHA-6713] Flush usage counters hourly and alert on Redis evictions (PR: #20412, Author: @hifaizsk)
• [CHA-5658] Enable engagement stats on us-west1 c3 (PR: #20403, Author: @ianb-gs)
• [FEEDS-2211] Per-app feeds export record caps configurable in Nessy (PR: #20402, Author: @dzoke)
• [CHA-6086] Run Jeffery's effort split at low (PR: #20419, Author: @adityaalifn)
• [CHA-6715] Don't flag a "none found" prompt-injection check (PR: #20423, Author: @adityaalifn)
• [VID-1698] Save and read snapshots to gcp buckets. (PR: #19982, Author: @vagruchi)
• [CHA-6677] Count oneshot teardown, retention and restore writes in stored gauges (PR: #20332, Author: @hifaizsk)
• [INF-2223] Shrink Paris staging cdn-proxy to one t3a.medium (PR: #20417, Author: @razkevich)
• Release v240.7.3 (PR: #20427, Author: @stream-ci-bot)