[Port dspace-9_x] Improve back navigation logic in ItemComponent

[Kasinhou]

Bug: Improve back navigation logic in ItemComponent

References

Port of #5170

Description

Improves the "Back to results" button logic on item pages by adding session storage as a fallback for the previous URL. This ensures the back button works correctly across page refreshes and prevents stale navigation when users visit items from different contexts (e.g. homepage vs. collection browse).

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[tdonohue]

👍 Thanks @Kasinhou ! I've reviewed this and verified it's an accurate backport of #5170. It includes all the same changes except the dataset.component.spec.ts changes (as dataset support is new in 10.0 and shouldn't be included in 9.x)