[DependencyInjection] fix XmlDumper when a tag contains also a 'name' property

[lyrixx]

Q	A
Branch?	6.4
Bug fix?	yes
New feature?	no
Deprecations?	no
Issues
License	MIT

Since #47364, the tag can contain an array of attributes.
And since #47364, SF uses it to store workflow metadata and also a name property.
It likely broke the XML generation, and so it brokes debug:router command for instance.
Sorry, I didn't notice it before!

Before the patch, I got that in my container var/cache/dev/App_KernelDevDebugContainer.xml

<tag>workflow<attribute name="name">article</attribute><attribute name="metadata"><attribute name="title">Manage article</attribute></attribute></tag>

After, I got

<tag name="workflow">
  <attribute name="name">article</attribute>
  <attribute name="metadata">
    <attribute name="title">Manage article</attribute>
  </attribute>
</tag>

[stof]

Actually, the PR you linked is not the one adding support for arrays in tag attributes (it is one that introduces a usage of such tag in the core).
Please identify the actual PR introducing that feature in the DI component, to identify the lowest affected branch.

[lyrixx]

@stof I updated the PR description, the target branch (6.4), and fixed tests

[nicolas-grekas]

Thank you @lyrixx.