[luSelect] Apply scroll on first loading with firefox

[jeremie-lucca]

Bug description

Since Angular 19, luSelect applies a scroll on first loading on Firefox:

Chrome

How to reproduce

• Open luSelect panel on Firefox

[vvalentin-lucca]

After investigation, it seems to be linked to the appearance of the lu-option-searcher that causes the shift, but I'm still unable to correct the problem.

Tested without success:

• transform3D;
• min-height: 0;
• disable animation;
• modify scroll-margin;
• remove internal and external margins;
• set fixed heights…