Corrects misleading error message in QuestionnaireViewModel

[vishnuravi]

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

An issue was not created as this is a straightforward change.

Description
Fixes error messages within QuestionnaireViewModel that reference incorrect property names.

Alternative(s) considered
No alternatives available.

Type
Bug fix

Screenshots (if applicable)
N/A

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).

[jingtang10]

Thanks so much!

FYI @stevenckngaa

[codecov]

Codecov Report

Merging #1461 (23736d9) into master (63fc76f) will increase coverage by 0.00%.
The diff coverage is 66.66%.

@@            Coverage Diff            @@
##             master    #1461   +/-   ##
=========================================
  Coverage     90.07%   90.07%           
  Complexity      648      648           
=========================================
  Files           129      129           
  Lines          9843     9844    +1     
  Branches        716      716           
=========================================
+ Hits           8866     8867    +1     
  Misses          591      591           
  Partials        386      386           

Impacted Files	Coverage Δ
...android/fhir/datacapture/QuestionnaireViewModel.kt	78.30% <66.66%> (+0.11%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c047cc3...23736d9. Read the comment docs.