Describe the bug
A clear and concise description of what the bug is.

Hello, I updated the scenario runner from
05a811a
to
e5b06cc

to get OpenScenario ParameterAction support. However, now it seems that the parsing of .xosc files is somehow broken. When a parameter is used in the .xosc file, the name of the parameter is passed on instead of the value assigned to the parameter.

To Reproduce
Steps to reproduce the behavior:

1. Declare a parameter in .xosc scenario file:

<?xml version="1.0"?>
<OpenSCENARIO>
  <FileHeader revMajor="1" revMinor="0" date="2021-05-04T00:00:00" description="CARLA:Template" author=""/>
  <ParameterDeclarations>
    <ParameterDeclaration name="route_entry_name" parameterType="string" value="Map01_testroute_maneuver"/>
  </ParameterDeclarations>

2. Use the parameter for something, e.g. retrieve a maneuver from catalog:

<ManeuverGroup maximumExecutionCount="1" name="ManeuverSequence">
  <Actors selectTriggeringEntities="false">
    <EntityRef entityRef="ego_vehicle"/>
  </Actors>
  <CatalogReference catalogName="ManeuverCatalog" entryName="$route_entry_name"/>
</ManeuverGroup>

Expected behavior
Before updating, this retrieved the catalog maneuver with name "Map01_testroute_maneuver" correctly.

Screenshots
Leads to:

This seems to affect all parameter usage in the .xosc file. Before updating the scenario runner everything was working well. I suspect the breaking changes are introduced by 8ed24c8, however I couldn't find the cause. Can others reproduce the issue, or could it still be something on my end?

Desktop (please complete the following information):

• OS: [Ubuntu 20.04
• CARLA Version 0.9.12 (docker shipped)
• Python version 3.7

I'm using the scenario runner through the ros-bridge.

Additional context
Add any other context about the problem here.