React: Investigate performance benefits from React Compiler

[dcblundell]

React Compiler is made to support React v19 but can be used on v18 (our current version). We should investigate the benefits of using this.

If we can upgrade to v19 relatively painlessly we should do it.

[dcblundell]

Blueprint issue for problems moving to R19 - palantir/blueprint#7115

"v6.0 will not include official support for React 19"

"As many of you have correctly pointed out, the primary blocker is our current dependency on react-popper. The path forward requires a significant refactor to migrate components that depend on Popover to a more modern positioning engine like @floating-ui/react. To be fully transparent, the core team maintaining Blueprint has limited resources, so we need to sequence these efforts carefully. Our priority is to first deliver the stability and improvements of v6.0, which includes foundational work that paves the way for this migration."

[dcblundell]

Moving to a future milestone to look at.