Fix #4491: Update wording for item_selection_text to prevent confusion to students.

[KevinGitonga]

Fix #4491: This fix updates the wording for "item_selection_text" to "Please select all correct choices" to prevent confusion.

Essential Checklist

• The PR title and explanation each start with "Fix #bugnum: " (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
• Any changes to scripts/assets files have their rationale included in the PR explanation.
• The PR follows the style guide.
• The PR does not contain any unnecessary code changes from Android Studio (reference).
• The PR is made from a branch that's not called "develop" and is up-to-date with "develop".
• The PR is assigned to the appropriate reviewers (reference).

For UI-specific PRs only

If your PR includes UI-related changes, then:

• Add screenshots for portrait/landscape for both a tablet & phone of the before & after UI changes
• For the screenshots above, include both English and pseudo-localized (RTL) screenshots (see RTL guide)
• Add a video showing the full UX flow with a screen reader enabled (see accessibility guide)
• Add a screenshot demonstrating that you ran affected Espresso tests locally & that they're passing

Before Portrait	After Portrait

Before Landscape	After Landscape

[BenHenning]

Thanks @KevinGitonga! I think this looks good, I just want to verify the testing situation. Also, for your PR please also:

• Make sure the PR description is formatted similarly to other PRs (I don't think you need a bullet item in this case)
• Make sure the PR title includes 'Fix' per other PR conventions
• Make sure the PR checklist is filled out
• Make sure to add screenshots of any affected Espresso tests still passing

There are also failing CI checks (which might suggest that some tests may need to be updated)--PTAL.

[BenHenning]

Thanks @KevinGitonga! LGTM.