fix(e2e): set number of li in contributions #5399

Job	Run time
Build	2m 39s
Register elasticsearch	15s
Lint Dockerfile	9s
Build Storybook	49s
Lint (@socialgouv/cdtn-ui)	42s
Lint (@cdt/frontend)	46s
Lint (@socialgouv/modeles-social)	1m 5s
Test (@socialgouv/cdtn-ui)	1m 47s
Test (@cdt/frontend)	5m 29s
Test (@socialgouv/modeles-social)	9m 29s
Check typescript types (@cdt/frontend)	47s
Check typescript types (@socialgouv/modeles-social)	33s
Check typescript types (@socialgouv/cdtn-utils)	18s
Check typescript types (@socialgouv/cdtn-ui)	34s
	25m 22s

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