Vector layer gets exported as an empty image if using a custom color profile

- [x] Bug report.
- [ ] Feature request.

## Bug report ##

**What is the current behavior?**

Vector layer does not exported (is not visible) BUT trimming respects the bounding box of the vector text!

**What is the expected behavior?**

Vector layer is visible in exported PNG:

**Tell us the steps to reproduce the bug, and if possible share a minimal demo of the problem.**

1. Get the file: https://www.dropbox.com/s/x8gddk0fnyw2bw8/gamejam_headlines_01.kra?dl=0
2. Click "All Layers" in the Batch Exporter
3. See that the file has the correct dimensions (after trimming) but the text is not readable.

Download the linked .kra file and reproduce the export through Batch Exporter's "All Layers" option with its custom color profile. Compare the resulting PNG with the expected visible vector text while preserving the trimmed dimensions. Done means the vector layer is readable in the exported PNG.

Written by the indexing model from the issue text.