Update the svMultiPhysics section with the new GUI svMultiPhysics updates

[ktbolt]

Problem

The svFSI Tool has been rebranded MultiPhysics.

Solution

Update the documentation for the svMultiPhysics Tool.

Additional context

No response

Code of Conduct

• I agree to follow this project's Code of Conduct and Contributing Guidelines

[ktbolt]

I've made all of the required textual changes.

The Tutorial images still have svFSI in the GUI, I'll update those images later.