Don't reuse global model params

[hellkite500]

Fixing bug in reuse of global model_params when linking external data from a global formulation definition

Changes

• Copy global formulation config before modifying with link_external

Testing

1. Tested on realization provided in Formulation Data Provider providing wrong data #871 and ensured each feature on the BMI receiving end has correct area values

Checklist

• PR has an informative and human-readable title
• Changes are limited to a single goal (no scope creep)
• Code can be automatically merged (no conflicts)
• Code follows project standards (link if applicable)
• Passes all existing automated tests
• Any change in functionality is tested
• New functions are documented (with a description, list of inputs, and expected output)
• Placeholder code is flagged / future todos are captured in comments
• Project documentation has been updated (including the "Unreleased" section of the CHANGELOG)
• Reviewers requested with the Reviewers tool ➡️

Target Environment support

• Linux
• MacOS