chore: refactor validate email otp and add firebase integration test

[NYARAS]

Signed-off-by: Otieno Calvine nyarangaotieno@gmail.com

Review Checklist

Summary*

• fix: Bug fix for Add the items tackled here as checklists
• feat: Completed task
• chore: Incomplete task
  • test: Sub-task 1

Structure*

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• Ensure dry running library to confirm changes

Tests

• Proper and high quality unit, integration and acceptance(if applicable) tests have been written
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Sign off*

• All comments have been resolved by the reviewers
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N/B:

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