Improves the page load speed for the Blaze app

[sbarbosa]

I am noticing a delay in the Blaze Dashboard app's response when it is loading. The main problem is that you can see the dashboard already rendered with all the posts, but you can't change tabs until the page fully loads.

The async functions that we have in Calypso + Blaze are preventing the app from fully loading quickly, and until the load event is triggered in the browser, the page package won't take any pop state from the hash.

From the user's point of view, you will see the tab changing, but the actual tab won't be rendered. After some time, it will start working.

Proposed Changes

• Show the first dashboard page when the load event is triggered.

Testing Instructions

• Connect to your sandbox and execute bin/install-plugin.sh blaze fix/blaze-app-load-speed
• Move the traffic from widgets.wp.com to your sandbox
• Open any self-hosted site (or any other site using Jetpack Blaze, like Pressable)
• Go to Tools->Advertising and verify that the page loads quickly and that you can change the tabs without seeing the previous behavior

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• https://wpcalypso.wordpress.com/devdocs/docs/testing/index.md for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:commit-a4d0f0adb8221a1828630c93c0577f74f81cb662

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:commit-a4d0f0adb8221a1828630c93c0577f74f81cb662&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:commit-a4d0f0adb8221a1828630c93c0577f74f81cb662&env=a8c-for-agencies

[matticbot]

This PR does not affect the size of JS and CSS bundles shipped to the user's browser.

Generated by performance advisor bot at iscalypsofastyet.com.