updated idl for activity task dispatch

[mkolodezny]

follow up #4813

[coveralls]

Pull Request Test Coverage Report for Build 5b8fb03b-8a9f-47b4-8b2a-0ef8adb0ee9d

• 0 of 28 (0.0%) changed or added relevant lines in 1 file are covered.
• 40 unchanged lines in 11 files lost coverage.
• Overall coverage decreased (-0.02%) to 56.989%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
common/types/mapper/thrift/matching.go	0	28	0.0%

Files with Coverage Reduction	New Missed Lines	%
common/task/weightedRoundRobinTaskScheduler.go	1	89.64%
common/types/shared.go	1	26.66%
common/membership/hashring.go	2	83.54%
common/types/mapper/thrift/matching.go	2	0%
common/util.go	2	51.17%
service/history/execution/mutable_state_builder.go	2	69.69%
service/matching/taskListManager.go	2	74.19%
common/types/mapper/thrift/shared.go	4	63.9%
service/history/task/transfer_active_task_executor.go	4	71.93%
service/history/execution/context.go	6	69.6%

Totals
Change from base Build 5787dcac-e026-4499-9541-5d8e2350a3b6:	-0.02%
Covered Lines:	83982
Relevant Lines:	147364

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💛 - Coveralls