Add `ament_mypy` to `rclpy` in `quality_of_service_demo`

[InvincibleRMC]

Description

Test with mypy --strict . --ignore-missing-imports --allow-untyped-calls.
Add test_mypy.py file and resolve all regressions. A copy can be found here

Motivation

Improve static typing throughout the ros2 core.

Design / Implementation Considerations

No response

Additional Information

No response

[exkson]

Hey @InvincibleRMC . I'd like to work on this one. Could you assign it to me ?

[Auditbyte25]

Hey @InvincibleRMC I will like to work on this issue.
Please assign me

[InvincibleRMC]

Hey @InvincibleRMC I will like to work on this issue. Please assign me

Sorry @exkson Is already assigned.

[ShivamMaurya14]

hi, @InvincibleRMC . if @exkson you are not working on issue .
Kindly assign to me . I want to give my first contribution to community.

[exkson]

Sorry, I'm currently not working on it.

[InvincibleRMC]

hi, @InvincibleRMC . if @exkson you are not working on issue . Kindly assign to me . I want to give my first contribution to community.

Done

[ShivamMaurya14]

hii, @InvincibleRMC
I've raised a PR for this issue link . Please review and suggest changes if any .
thank you .