Remove id column from vulnerability_reads table

What does this MR do and why?

This MR adds a database migration to remove the id column from the vulnerability_reads table.

The vulnerability_reads table currently has both an id column and uses vulnerability_id as the primary key. This design causes several issues:

1. Rails 7.2 Compatibility: Rails treats id as a special attribute that maps to the primary key, causing issues with bulk insert operations (as seen in !209592 (merged))
2. Confusion: Having both id and vulnerability_id columns where only vulnerability_id is used as the primary key creates confusion
3. Unnecessary Storage: The id column serves no functional purpose since all operations use vulnerability_id

Benefits of removing the id column:

• Resolves Rails 7.2 bulk insert compatibility issues
• Reduces table size and index overhead
• Eliminates confusion about which column is the actual primary key
• Simplifies the model structure

Database Impact

• Table: vulnerability_reads
• Operation: DROP COLUMN id
• Reversibility: The migration includes a down method that recreates the column, but note that original id values cannot be restored

References

• Related issue: #357262
• Context from MR: !209592 (merged) (Fix bulk insert of vulnerability reads in Rails 7.2)

MR acceptance checklist

This MR:

• Includes a database migration
• Has been tested for reversibility
• Addresses a specific Rails 7.2 compatibility issue
• Simplifies the data model by removing an unused column