Fix bug with export pattern modal

[philip-cline]

Checklist

• Appropriate branch selected (all PRs must first be merged to dev before they can be merged to master)
• Any modified or new methods or classes have helpful JSDoc and code is thoroughly commented
• The description lists all applicable issues this PR seeks to resolve
• The description lists any configuration setting(s) that differ from the default settings
• All tests and CI builds passing

Description

The old modal was replaced rather than just supplemented by the new pattern export modal. This PR makes the pattern export modal a separate ref and only opens it on the export button being clicked.

[miles-grant-ibigroup]

Haven't had time to test this but it looks good

[binh-dam-ibigroup]

Delete snapshot works as intended per the client-reported issue. Looks like there was a spinner shown in the "Take snapshot" button from the snapshot list that was also fixed.