Fix Python server implementation

[BSchilperoort]

During testing two issues arose;

• connexions passes a single argument as "body", so this broke some of the setters.
• get_value_at_indices had arguments turned around for the model call

Using the BMI Controller and the BMI Heat example I was able to validate these methods now work correctly.

[sverhoeven]

Good catch.

Tested it with heat and Swagger UI

uv pip install git+https://github.com/csdms/bmi-example-python
uv pip install connexion[swagger-ui]
# Set swagger_ui=True in python/src/remotebmi/server/__init__.py
wget https://github.com/csdms/bmi-example-python/raw/refs/heads/master/examples/heat.yaml
BMI_MODULE=heat BMI_CLASS=BmiHeat uv run run-bmi-server

Seems R has args in get_value_at_indices swapped in spec. and model wrapped by server is not passing dest.