refactor: Update LoginRequest struct validation in request.go

[henrriusdev]

• Update the LoginRequest struct in request.go to include validation tags for the 'email' and 'password' fields.
• Add the 'required' and 'email' validation tags to the 'email' field.
• Add the 'required', 'min=8', and 'max=64' validation tags to the 'password' field.