Add more weekday operator and sensor examples #26071

[cra]

Hello

This PR contains the following:

• adds more examples and explicit mention of imports of WeekDay enum in BranchDayOfWeekOperator.
• adds back reference to now-deprecated kwarg, mentions that you should not use it (I saw something similar in the docs for other deprecated params and would think it's a good idea to have it in the docs since it's in the constructor)
• adds more tasks in dag example for BranchDayOfWeekOperator so it's hopefully clearer on how to use WeekDay enum.
• somewhat code-affecting change: adds type hints for the weekday sensor. I also updated hints for the week_day so it has the enum in it

It all should add more examples to both HowTo for the operator and the operator/sensor description in the docs

closes: #26071

[potiuk]

Nice one!

[boring-cyborg]

Awesome work, congrats on your first merged pull request!