D8: Improve tmp file handling when uploading H5Ps

Description

See patch submitted here: https://www.drupal.org/node/2908953

Environment

None

Acceptance Criteria

1. Determine if this will cause any issues, i.e. when temporarily viewing content in the editor before saving.
2. Apply patch

Status

Assignee

Frode Petterson

Reporter

Frode Petterson

Labels

Funding

None

Code reviewer

None

Released

None

Time tracking

6h

Fix versions

None

Sprint

None

Priority

Medium