Xporter is not updating the progress bar properly

Xporter is not uploading the progress bar properly on Dialog and background export.

In some cases, Xporter is updating the progress bar to 88% directly.

Steps to reproduce the error:

1. Add multiple tests to one specific Test Execution (ex.: 150 tests)
2. Perform the exportation (Bulk Export) using the template from our store (Test Execution Advanced with the cover page)
3. Send the exportation to the background
4. Access My Exports page

Current behavior:

Xporter goes from 0% to 88% directly without giving feedback about if the export already started.

Expected behavior:

Xporter should give feedback if the exportation already started instead of keeping in 0%.

Note: Check the same behavior on Test Plan exportation using the Test Plan Advanced with cover page.