Add null check in ConditionVersion of Set-AzRoleAssignmenr (#12829)

* add missing null check

* update docs

* Remove old TODO

Author: dagoroz

src/Resources/Resources/ChangeLog.md

@@ -18,6 +18,7 @@
         - Additional information about change #1
 -->
 ## Upcoming Release
+* Added missing check for Set-AzRoleAssignment
 * Added breaking change attribute to `SubscriptionId` parameter of `Get-AzResourceGroupDeploymentOperation`
 * Updated ARM template What-If cmdlets to show "Ignore" resource changes last
 * Fixed secure and array parameter serialization issues for deployment cmdlets [#12773]

src/Resources/Resources/RoleAssignments/SetAzureRoleAssignmentCommand.cs

@@ -112,8 +112,8 @@ public override void ExecuteCmdlet()
             }
 
             // If ConditionVersion is changed, validate it's in the allowed values
-            var oldConditionVersion = double.Parse(InputObject.ConditionVersion);
-            var newConditionVersion = double.Parse(fetchedRole.ConditionVersion);
+            var oldConditionVersion = double.Parse(InputObject.ConditionVersion ?? "0.0");
+            var newConditionVersion = double.Parse(fetchedRole.ConditionVersion ?? "2.0");
 
             // A condition version can change but currently we don't support downgrading to 1.0
             // we only verify the change if it's a downgrade