Update information about the responsibilities of TW and EM

Why is this change being made?

There was a change that made it in !42566 (diffs), that shifted the responsibility of the Engineering Manager to the Technical Writer. This should not have been done.

This MR fixes this and makes sure the responsibilities of a Technical Writer and an Engineer Manager are clarified when it comes to reviewing the individual release post items.

Closes #6859 (closed)

Does this MR meet the acceptance criteria?

Assign to DRI

• Did you assign this change to the correct DRI of the page or information you are changing?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what