Open the first n topics by m levels by default when accessing the topic hierarchy

[cstns]

Epic

No response

Description

In order to ease data visualization, we should open the first n root topics with an m number of nested levels.

The reasoning behind not opening all topics at once is to not block the page on high dom renders on huge payloads.

Which customers would this be available to

Everyone - CE/Starter/Team/Enterprise

Acceptance Criteria

Open the first n topics by m levels by default when accessing the topic hierarchy.

Have you provided an initial effort estimate for this issue?

I have provided an initial effort estimate

[cstns]

the test/e2e/frontend/cypress/tests-ee/uns/hierarchy.spec.js:66 e2e test should be altered as well