Fix the condition for mask export.

[Arkkienkeli]

This branch solves #326, when export did not work properly without masks.
The current behaviour is the following:
if outlines field and mask_objects:true are both in the config - then the cells are exported with masks
if no outlines field and mask_objects:false in the config - the cells are exported without masks correctly
if no outlines field and mask_objects:true in the config - DeepProfiler will crash.

I was wondering if we want the following functionality later: export masked cells right away without saving the mask itself.

[vasudev-sharma]

Hi @Arkkienkeli, thanks for this PR which aims to resolve the issue #326. Although this PR hasn't been merged into the master branch, I was wondering can I use this branch to resolve the issue I was facing earlier?

[Arkkienkeli]

Hi @vasudev-sharma sorry for not coming back to that,
yes it did work and I guess I am going to merge it for now as is.