Show the loading UX immediately when importing a resource model #10540

[MikeGriniezakis]

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Description of Change

Currently, the loading UX is not being rendered when importing a resource model.
This PR changes the graph page to show the loading UX as soon as the import begins.

Issues Solved

Closes #10540

Checklist

• I targeted one of these branches:
  • dev/8.0.x (under development): features, bugfixes not covered below
  • dev/7.6.x (main support): regressions, crashing bugs, security issues, major bugs in new features
  • dev/6.2.x (extended support): major security issues, data loss issues
• I added a changelog in arches/releases
• I submitted a PR to arches-docs (if appropriate)
• Unit tests pass locally with my changes
• I added tests that prove my fix is effective or that my feature works
• My test fails on the target branch