Allow sequence templates to link to multiple model versions

Checked for duplicates

Yes - I've already checked

Alternatives considered

Yes - and alternatives don't suffice

Related problems

No response

Describe the feature request

Currently sequence templates are linked to a specific activity type in a specific model. That means if a new version of that model is uploaded, there is no shared association between the original sequence templates and the new model. During mission model development we've updated the model many times without changing sequence templates and so for each new model we need to either a) transfer the model ID linkages from the old model to new for all sequence templates (rendering the old model unusable w. command expansion), or b) re-upload all the templates despite having no changes. To expedite the process and avoid uploading duplicate data, it would be great if we could link a single template to an activity type across multiple models/versions.

Start by tracing how sequence templates associate an activity type with a model, then inspect the model-version and command-expansion paths. Determine where the single-model linkage is enforced and how old and new model versions are represented. Done means one template can be associated with an activity type across multiple model versions without re-uploading it, while existing model use remains intact.