Replace all the hardcoded task type and action string comparisons

### Description

We have a bunch of code that checks task types and actions using inline strings, and they are duplicated all over the codebase.

Example: `checkedAction == "reject"`.

Replace these strings with something nicer. Value objects or static read only strings, or something...

Anything.

### Additional Information

Probably want to do it in storage interfaces package, since storage also has the same kind of strings.

### Acceptance Criterias

All cases are removed.

Start by searching the codebase for inline task type and action comparisons such as `checkedAction == "reject"`, then inspect the storage interfaces package where similar strings are reported. Decide on a consistent replacement approach and verify that all such cases have been removed.

Written by the indexing model from the issue text.