[WORKFLOW SDK BUG] Activity concurrency is throttled too much

**runtime**
1.17.rc2

**SDK**
dapr>=1.17.0rc2
dapr-ext-workflow>=1.17.0rc2

## Expected Behavior

Activities are allowed to run concurrently

## Actual Behavior

The SDK is throttling how many activities can be ran at any one point time

## Steps to Reproduce the Problem

Create a workflow, fan out 100 instances of Activities, have each activity sleep for 60 seconds before completing.

Look at the logs and notice that there are at most 10-15 activities running at the same time. Despite all Activities being **scheduled** at the same time, Activities won't **Activate** untill previous activities have **finished**.

Look at the timestamps in the logs below

note : When comparing this exact same workflow authored in dotnet, dotnet allows all activities to run concurrently.

```
2026-01-27 12:49:47

2026-01-27 12:49:47,810 - hello_world_app.workflows.fan_out_workflow - INFO - Starting fan-out workflow with 100 iterations
2026-01-27 12:49:47

2026-01-27 12:49:47.812 durabletask-worker INFO: 0-312: Orchestrator yielded with 100 task(s) and 0 event(s) outstanding.
2026-01-27 12:49:47

2026-01-27 12:49:47,812 - hello_world_app.workflows.fan_out_workflow - INFO - Waiting for 100 activities to complete
2026-01-27 12:49:47

2026-01-27 12:49:47,812 - durabletask-worker - INFO - 0-312: Orchestrator yielded with 100 task(s) and 0 event(s) outstanding.
2026-01-27 12:49:47

2026-01-27 12:49:47,824 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #0 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,826 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #1 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,826 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #2 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,828 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #3 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,829 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #4 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,833 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #5 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,835 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #6 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,846 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #7 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,855 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #8 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,865 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #9 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,866 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #10 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,869 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #11 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,870 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #12 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

2026-01-27 12:49:47,872 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #13 - scheduled=12:49:47 activated=12:49:47
2026-01-27 12:49:47

INFO: 172.20.0.11:53174 - "POST /fanout-workflow HTTP/1.1" 200 OK
2026-01-27 12:50:47

2026-01-27 12:50:47,827 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #0 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,831 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #1 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,832 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #3 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,832 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #2 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,833 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #4 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,834 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #5 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,836 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #6 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,845 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #14 - scheduled=12:49:47 activated=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,845 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #15 - scheduled=12:49:47 activated=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,846 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #16 - scheduled=12:49:47 activated=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,847 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #17 - scheduled=12:49:47 activated=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,847 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #18 - scheduled=12:49:47 activated=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,848 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #19 - scheduled=12:49:47 activated=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,849 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #7 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,850 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #20 - scheduled=12:49:47 activated=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,852 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #21 - scheduled=12:49:47 activated=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,857 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #8 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,859 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #22 - scheduled=12:49:47 activated=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,867 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #9 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,868 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #10 - scheduled=12:49:47 activated=12:49:47 finished=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,870 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #23 - scheduled=12:49:47 activated=12:50:47
2026-01-27 12:50:47

2026-01-27 12:50:47,870 - hello_world_app.activities.super_slow_activity - INFO - 0-312 - super_slow_activity (1) #24 - scheduled=12:49:47 activated=12:50:47
```

## Release Note

RELEASE NOTE: