Fix dynamic upload cancellation not carrying forward

[MikeEvansSkillsVR]

Description

When clicking cancel on the Upload Dynamic Objects unity editor window, the cancellation does not carry forward to all remaining dynamic object uploads. Resulting in a non-clickable cancel button, meaning you are forced to wait for the remaining dynamic objects to finish uploading.

Type of change

Note: delete the lines that are not applicable and check the boxes for the type of change.

• Bug fix (non-breaking change which fixes an issue)

Checklist

These look to be for internal PRs? Ticked what I know

• My changes will not interrupt or disrupt automated build processes
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• My changes generate no new warnings