fix(shard-distributor): change to migration dynamic config name (#7441)

<!-- Describe what has changed in this PR -->
**What changed?**
Changed to use the standard naming convention was not reflected in
development config

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**Why?**
when starting the services only the namespaces with default behavior
where receiving the righe configuration from SD. the misconfigured ones
were still operating since the result was an invalid migration mode, but
the shadow mode was not really tested in local environment after the
change of the property name.

<!-- How have you verified this change? Tested locally? Added a unit
test? Checked in staging env? -->
**How did you test it?**
local development

<!-- Assuming the worst case, what can be broken when deploying this
change to production? -->
**Potential risks**
no, only affect local development

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data migration required? If so, please mention it, and also update
CHANGELOG.md -->
**Release notes**

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https://cadenceworkflow.io/docs/operation-guide/setup/ ? If so, please
open an PR in https://github.com/cadence-workflow/cadence-docs -->
**Documentation Changes**

Signed-off-by: edigregorio <[email protected]>

Author: eleonoradgr

config/dynamicconfig/development.yaml

@@ -75,17 +75,17 @@ system.domainAuditLogTTL:
   - value: "15m"
 matching.enableClientAutoConfig:
 - value: true
-shardDistributor.MigrationMode:
+shardDistributor.migrationMode:
   - value: "onboarded"
   - value: "local_pass"
     constraints:
-    namespace: "test-local-passthrough"
+      namespace: "test-local-passthrough"
   - value: "local_pass_shadow"
     constraints:
-    namespace: "test-local-passthrough-shadow"
+      namespace: "test-local-passthrough-shadow"
   - value: "distributed_pass"
     constraints:
-    namespace: "test-distributed-passthrough"
+      namespace: "test-distributed-passthrough"
   - value: "distributed_pass"
     constraints:
-    namespace: "test-external-assignment"
+      namespace: "test-external-assignment"