Scenario delivery data templates not rendered before transport call

[lollox80]

When a scenario overrides delivery data with Jinja2 templates
(e.g. volume, volume_level, method), the templates are not resolved
before being passed to the transport.

Example — scenario morning overrides alexa_announce.data.volume:
data:
volume: "{{ (states('input_number.notifier_morning_volume') | float(40)) / 100 }}"

The archive shows the raw template in data.volume, and the actual
call to alexa_media omits volume entirely.

Expected: volume resolved to e.g. 0.4 before the transport call
Actual: raw template string passed, transport ignores unknown field

Affects: any scenario using dynamic values in delivery data
(volume, volume_level, method, etc.)

Note: related to the planned work in _render_scenario_templates