handle numpad enter on Sign in page form

[indirectlylit]

Summary

On an extended keyboard, pressing the numpad 'enter' key wasn't working during sign-in

before	after

Reviewer guidance

make sense?

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Contributor Checklist

PR process:

• PR has the correct target branch and milestone
• PR has 'needs review' or 'work-in-progress' label
• If PR is ready for review, a reviewer has been added. (Don't use 'Assignees')
• If this is an important user-facing change, PR or related issue has a 'changelog' label
• If this includes an internal dependency change, a link to the diff is provided

Testing:

• Contributor has fully tested the PR manually
• If there are any front-end changes, before/after screenshots are included
• Critical user journeys are covered by Gherkin stories
• Critical and brittle code paths are covered by unit tests

Reviewer Checklist

• Automated test coverage is satisfactory
• PR is fully functional
• PR has been tested for accessibility regressions
• External dependency files were updated if necessary (yarn and pip)
• Documentation is updated
• Contributor is in AUTHORS.md

[codecov]

Codecov Report

Merging #7095 into release-v0.14.x will increase coverage by 0.12%.
The diff coverage is 0.00%.

Impacted Files	Coverage Δ
...libri/plugins/user/assets/src/views/SignInPage.vue	35.09% <0.00%> (-0.24%)	⬇️
kolibri/core/tasks/utils.py	89.65% <0.00%> (-3.45%)	⬇️
kolibri/utils/options.py	77.98% <0.00%> (ø)
kolibri/__init__.py	100.00% <0.00%> (ø)
kolibri/core/content/utils/check_schema_db.py	100.00% <0.00%> (+8.69%)	⬆️