minor #46671 [Workflow] Add a nice exception message when unexpected …

…data is passed to Marking (Nyholm)

This PR was merged into the 6.2 branch.

Discussion
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[Workflow] Add a nice exception message when unexpected data is passed to Marking

| Q             | A
| ------------- | ---
| Branch?       | 6.2
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       |
| License       | MIT
| Doc PR        | n/a

During my Workshop during Symfony online, one of my attendees got an exception message they didn't really undersand.
They ran
```php
$this->workflow->apply($subject, 'foobar');
```
But got the error `Marking::__construct() expects array, string passed`.

Their issue was that `$subject->getPlaces()` returned a string. It was pretty hard to figure out from that exception message, so I thought we could improve.

Commits
-------

2e4bd96 [Workflow] Add a nice exception message when unexpected data is passed to Marking

src/Symfony/Component/Workflow/MarkingStore/MethodMarkingStore.php

@@ -70,6 +70,8 @@ public function getMarking(object $subject): Marking
 
         if ($this->singleState) {
             $marking = [(string) $marking => 1];
+        } elseif (!is_array($marking)) {
+            throw new LogicException(sprintf('The method "%s::%s()" did not return an array and the Workflow\'s Marking store is instantiated with $singleState=false.', get_debug_type($subject), $method));
         }
 
         return new Marking($marking);