Replace reference of section to sub-department in senior frontend engineer responsibility

Why is this change being made?

The usage of section in this previous wording is now being replaced with the word sub-department

How will this merge request impact page speed?

Minimal

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