Continue processing SubModuleOverrides if neither Regex text nor Replacement field were found

[artifixer]

Currently SubModuleOverrides stops processing with non-blocking error if Replacement text is empty for any overrides. This happens even of there when searched text was not found in the SubModule.xml and leads to the faulty SubModule.xml generation.

Suggested fixes:

1. Make build fail with error if searched text was found in the SubModule.xml, but Replacement text is empty.
2. Ignore cases where Replacement text was empty if there were no searched text entrances in the SubModule.xml. Ensure that all other SubModuleOverrides will be processed.