chore(ci): Update lading to 0.25.3, lower resource allocations in experiments (#22147)

Update lading to 0.25.3, lower resource allocations in experiments

This commit updates lading to the latest release which resolves some known
crashes and likewise we reduce the allocation granted to Vector in its
experiments as high resource allotment may also cause experiment failure.

Signed-off-by: Brian L. Troutwine <brian.troutwine@datadoghq.com>