Fix answer option match for coding initial expression

[parthfloyd]

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

Fixes #2880

Description
Replaced deep equal check for answerOption in populateInitialValues to a more custom logic for Coding Type & keeping the behavior same for other types.

Alternative(s) considered
None | Looking forward to feedback

Type
Bug fix

Screenshots (if applicable)

Checklist

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[jingtang10]

this is just testing the createObservationChoiceQuestionnaire function no? i don't think this is necessary.

the important thing in the test case is below: the generated questionnaire response from the population process includes selected answers.

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actually, this reveals a problem in the populate function (thanks laz for pointing out) i dont' think it should change the questionnaire... can you fix that?

[parthfloyd]

Thanks @jingtang10 for the feedback. Yes absolutely.
To confirm, refactoring populate function to modify/update only the questionnaireResponse answers. (rather than current approach of modifying questionnaire's initial or answerOption.selectedAnswer)
cc: @LZRS

[parthfloyd]

Update I've modified functions based on feedback.
Please feel free to let me know if any changes are required.
CC: @LZRS , @jingtang10