ui: Flamegraph rendering improvements

[manojVivek]

Contains:

• Memoized a bunch of render block computation in FlameNode component.
• Improved viewport culling to render only the nodes in the visible parts of the container.
• Added a useBatchedRendering to incrementally add flame nodes to the dom to prevent fps drop.

Before:

After:

This has removed the big drop in fps when rendering the flamegraph from the skeleton loader.

[alwaysmeticulous]

✅ Meticulous spotted 0 visual differences across 318 screens tested: view results.

Meticulous evaluated ~5 hours of user flows against your PR.

_{Expected differences? Click here. Last updated for commit 7d8444d. This comment will update as new commits are pushed.}

[metalmatze]

Very cool!