chore: update webviews to retain context when hidden

[scottdover]

Summary:
This changes how DataViewer maintains context. In our first iteration, retainContextWhenHidden: true was avoided because the documentation said:

keep in mind that this has high memory overhead and should only be used when other persistence techniques will not work

With that in mind, the implementation relied on re-fetching data each time a view was displayed. As DataViewer grows increasingly complex, the amount of state required to persist/fetch data will be increase.

Thus, this PR changes things such that we retain context when switching between tabs. The downside is that there is a higher memory footprint (it was hard to find data on this but a stack overflow post suggested an empty web view using retainContextWhenHidden: true consumes 50mb of memory). However, there are numerous upsides:

• Bugs like this go away entirely: Table Viewer - Maintain selected row when changing between windows #1791
• Grid state no longer has to be persisted/fetched when a tab is displayed
• The excess xhr requests that were made to re-fetch data are no longer needed
• From a developer perspective, adding new features to the dataviewer will require less time worrying about data persistence/retrieval for things that should be in-memory

Testing:

• Open a table, apply filters & sorts, change scroll position, etc
• Tab away and back to table, and make sure state hasn't changed