[FIX] Topic Modelling - Do not recompute when spin value doesn't change

[PrimozGodec]

Issue

Topic modelling run recomputation everytime spin focus is lost (even when value doesn't change)

Description of changes

Do not rerun if spin value doesn't change

Includes

• [X] Code changes
• [ ] Tests
• [ ] Documentation

[ajdapretnar]

This was such a simple solution! Amazing. :)