XWIKI-22540: Slow loading time when changing the icons theme to Silk in the Icon picker

[Sereza7]

Jira URL

https://jira.xwiki.org/browse/XWIKI-22540

Changes

Description

• Added a flag on the data_icons action to only retrieve metadata when necessary. This shaves off half of the time for the request and reduces significantly the size of the payload
• Updated slightly the IconPicker javascript to improve readability

Clarifications

• This PR is not enough to close the ticket, this represents a 50% reduction in the waiting time but it's still too high. Closing it will happen only when we can figure out a way to speed up loading icons, with https://jira.xwiki.org/browse/XWIKI-11112 for example.

Screenshots & Video

N/A, performance issue only

Executed Tests

Manual tests, time to display was reduced by half. Locally, the request before the changes would take about 5 seconds. This was most of the waiting time. After the PR, this request was only half as long (2 to 2.5s).

Expected merging strategy

• Prefers squash: Yes
• Backport on branches:
  • None, same as XWIKI-12013: Sort the icons alphabetically in the icon picker #3286