Allow additional grouping variables in the ratios table

[Gero1999]

Issue

Closes #868

Description

• Updated the tab_nca_server function to pass extra_group_vars into the NCA setup server module.
• Enhanced the ratios_table_server function to join and use the extra grouping variables when determining ratio groups, improving flexibility in ratio calculations.

Definition of Done

• ability to select additional grouping vars as ref/test parameters for ratios
• ratios calculated correctly

How to test

Map data (with Other grouping variables as variables of interest) > NCA setup > Ratios Table > Choose the ratios to perform using variables > Check if results are the ones expected

Contributor checklist

• Code passes lintr checks
• Code passes all unit tests
• New logic covered by unit tests --> Tests will be partially addressed in Closes #875 add tests for format data to reach 100 #909
• New logic is documented
• App or package changes are reflected in NEWS
• Package version is incremented

[Shaakon35]

LGTM

[js3110]

@Gero1999 I am unable to calculate any ratios using the dummy data and additional grouping variables- everytime I get the message Error calculating NCA results: numbers of columns of arguments do not match

Is this supposed to happen? is there a way to test that the ratios are working?

[js3110]

LGTM!