Remove unused organization_user_aliases table

What does this MR do and why?

Remove unused organization_user_aliases table

This table was introduced for a potential feature, but before the feature was rolled out it was superceded by the organization_user_details table. Since this table was never used, it should be removed to keep our codebase and db clean.

References

• Removal issue: #546252 (closed)
• Table created in MR !189052 (merged)
• Superceded by table organization_user_details in MR: !191575 (merged)

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. bundle exec rspec spec/models/user_spec.rb spec/models/organizations_spec.rb

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Related to #546252 (closed)