fix: HL parameters being NA for no reason & flags with no rules (#896)

[Gero1999]

Issue

Closes #896

Description

This pull request updates the logic for determining which pharmacokinetic parameters should be imputed in the apply_imputation function. The main change is to expand the set of parameters considered dependent on half-life or lambda.z, ensuring that imputation is skipped for parameters that depend on these as well as AUC/AUMC.

Imputation logic improvements:

• Expanded the set of parameters (params_hl_dep) to include those related to lambda.z and half.life in addition to auc and aumc, both in the parameter name and dependencies, to more accurately identify parameters that should not be imputed.
• Updated the filtering logic for params_not_to_impute to use the new params_hl_dep set, ensuring that any parameter depending on AUC, AUMC, lambda.z, or half-life is excluded from imputation.

Definition of Done

• If rules are not selected, they should not be applied to the NCA calculation.

How to test

In dummy data, add manual selection to Subj 1, Range 6:7. Run NCA and view that row is "MISSING" this is expected. Then deselect all rule sets and rerun, row is still "MISSING".

Contributor checklist

• Code passes lintr checks
• Code passes all unit tests
• New logic covered by unit tests
• New logic is documented
• App or package changes are reflected in NEWS
• Package version is incremented

Notes to reviewer

Anything that the reviewer should know before tacking the pull request?

[js3110]

@Gero1999 as discussed in person, the original issue/how to test seems to be different in main now, so this issue may need redefining. Could you take a look and also add a how to test for the PR? thanks!