populate initial with initialExpression result collection

[parthfloyd]

IMPORTANT: All PRs must be linked to an issue (except for extremely trivial and straightforward changes).

Fixes #2750

Description
Updated populateInitialValue() function in ResourceMapper.kt of the SDC module to populate questionnaireItem.initial with values of collection instead of just the first value of the collection.

Alternative(s) considered
None | Looking forward to feedback

Type
Bug fix

Screenshots (if applicable)

Checklist

• I have read and acknowledged the Code of conduct.
• I have read the Contributing page.
• I have signed the Google Individual CLA, or I am covered by my company's Corporate CLA.
• I have discussed my proposed solution with code owners in the linked issue(s) and we have agreed upon the general approach.
• I have run ./gradlew spotlessApply and ./gradlew spotlessCheck to check my code follows the style guide of this project.
• I have run ./gradlew check and ./gradlew connectedCheck to test my changes locally.
• I have built and run the demo app(s) to verify my change fixes the issue and/or does not break the demo app(s).

[LZRS]

To support multiple initially selected options from the dropdown, not quite sure populating the Questionnaire.item.initial would work.
From this Questionnaire.item.initial invariant

que-11 Rule If one or more answerOption is present, initial cannot be present. Use answerOption.initialSelected instead answerOption.empty() or initial.empty()

I would suggest maybe using Questionnaire.item.answerOption.initialSelected instead

[parthfloyd]

@LZRS Thank you so much for your feedback!
I've pushed code & now it's conforming with the invariant rules. Please feel free if any changes or optimizations are required in the code.

Invariant:

que-8 Rule Initial values can't be specified for groups or display items

que-13 Rule Can only have multiple initial values for repeating items

que-11 Rule If one or more answerOption is present, initial cannot be present. Use answerOption.initialSelected instead

cc: @jingtang10 , @icrc-jofrancisco

[LZRS]

LGTM

[jingtang10]

i think this can just be incorporated into the check. so you have:

check(
        !(questionnaireItem.type == Questionnaire.QuestionnaireItemType.GROUP ||
          questionnaireItem.type == Questionnaire.QuestionnaireItemType.DISPLAY) || (questionnaireItem.initial.isEmpty() && questionnaireItem.initialExpression == null),
      )

or maybe rephrase it somehow ^

[jingtang10]

so in this else block, the anwerOption is empty in the questionnaire item? why do we have to do anything in this case?

[jingtang10]

pls also reflect these changes with new test cases.