feat(users): Send welcome to community email in magic link signup

[ThisIsMani]

Type of Change

• Bugfix
• New feature
• Enhancement
• Refactoring
• Dependency updates
• Documentation
• CI/CD

Description

Magic link will send one more email along with magic link email if user is signing up.

Additional Changes

• This PR modifies the API contract
• This PR modifies the database schema
• This PR modifies application configuration/environment variables

Motivation and Context

Closes #6638.

How did you test it?

Local SES

curl --location 'http://localhost:8080/user/connect_account' \
--header 'Content-Type: application/json' \
--data-raw '{
    "email": "new user email"
}'

The above email should be sent.

Checklist

• I formatted the code cargo +nightly fmt --all
• I addressed lints thrown by cargo clippy
• I reviewed the submitted code
• I added unit tests for my changes where possible

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
crates/router/src/core/user.rs	4% smaller
crates/router/src/consts/user.rs	0% smaller
crates/router/src/services/email/assets/welcome_to_community.html	0% smaller
crates/router/src/services/email/types.rs	0% smaller

[racnan]

shadowing the variable.