Data profiler plugin does not calculate nulls/non nulls correctly

Data profiler plugin does not calculate count for nulls/non nulls correctly due to the condition at

Steps to reproduce:

1. Create BQ table with null values for a column

2. Create batch pipelines with BQ Source → Data Profiler → BQ Sink

3. Run the pipeline

4. Observe that categorical.nulls is 0 and categorical.non_nulls is the total row count.