front: fix selectableSlot in useLinkedTrainSearch #17611

Job	Run time
Check dockerfiles	14s
Build (core-build, core)	14s
Build (editoast, editoast-test)	26s
Build (gateway-test, gateway-standalone, gateway-front)	2m 21s
Check generated railjson sync	22s
Build (front-build, front-tests, front-devel, front-nginx)	2m 25s
Check scripts	6s
Build (osrdyne, osrdyne-test)	13s
Check commits	8s
Check final newline	9s
Check infra schema sync	14s
Check integration tests	1m 18s
Check osrd schema	44s
Check railjson generator	1m 55s
Check toml	8s
Check reuse compliance	9s
Check editoast tests	6m 42s
Check core	4m 7s
Check editoast openapi	49s
Check editoast lints	8m 42s
Check front	3m 6s
Check front rtk sync	1m 15s
Check gateway	3m 25s
Check osrdyne	3m 45s
End to end tests	16m 23s
Integration tests	1m 5s
	1h 0m 25s

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