Fix/pupil journey units filter

[kimon-satan]

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• Check component hierarchy is followed correctly
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A bunch of fixes to Accordians and the OakPupilJourneyUnitsFilter to make them suitable for pupil-760

• OakPupilJourneyUnitsFilter has an interface which is not based on indexed position
• Ensure Mobile Accordian stretches to full width of screen
• Simply Components where there is redundancy
• Improve nomenclature
• Fix any minor style errors
• Export test helpers which are now needed to support tests in OWA

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[benprotheroe]

appoved with comments

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud