[Demo] Fix demo by PHPStan findings + pipeline

[chr-hertel]

Q	A
Bug fix?	yes
New feature?	no
Docs?	no
Issues
License	MIT

Turns out pipeline was not running phpstan on the demo - this PR adds that and fixes the open issues.

[chr-hertel]

@OskarStark need your help here with the conditional return on the vectorizer - breaks my head or maybe just too late

this code:

ai/demo/src/Blog/Command/QueryCommand.php

Lines 44 to 52 in a4747cb

	$search = $io->ask('What do you want to know about?', 'New Symfony Features');
	$io->comment(\sprintf('Converting "%s" to vector & searching in Chroma DB ...', $search));
	$io->comment('Results are limited to 4 most similar documents.');
	$vector = $this->vectorizer->vectorize($search);
	$queryResponse = $collection->query(
	queryEmbeddings: [$vector->getData()],
	nResults: 4,
	);

with this return:

ai/src/store/src/Document/VectorizerInterface.php

Lines 29 to 37 in a4747cb

	* @return Vector|VectorDocument|array<Vector>|array<VectorDocument>
	*
	* @phpstan-return (
	* $values is string|\Stringable ? Vector : (
	* $values is EmbeddableDocumentInterface ? VectorDocument : (
	* $values is array<string|\Stringable> ? array<Vector> : array<VectorDocument>
	* )
	* )
	* )

leads to:

------ --------------------------------------------------------------------------------------------------------------- 
  Line   src/Blog/Command/QueryCommand.php                                                                              
 ------ --------------------------------------------------------------------------------------------------------------- 
  50     Cannot call method getData() on array<Symfony\AI\Platform\Vector\Vector|Symfony\AI\Store\Document\VectorDocum  
         ent>|Symfony\AI\Platform\Vector\Vector|Symfony\AI\Store\Document\VectorDocument.                               
         🪪  method.nonObject                                                                                           
 ------ --------------------------------------------------------------------------------------------------------------- 

[chr-hertel]

Used @phpstan-ignore-line for now to get the demo green again and phpstan integration going there.

Follow up with #768