Fix for fallback file upload (#14892)

* Added check for file type

* Removed unneeded null checks and fixed tabs

* Cleaning

* Cleanups, cleanups, and removal of unneeded null checks

* Reverted removal of relationshipservice

* Revert null check removals (too risky)

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Co-authored-by: Ambert van Unen <AvanUnen@ilionx.com>
Co-authored-by: Laura Neto <12862535+lauraneto@users.noreply.github.com>