Make consistent the category names displayed in recently accessed courses and starred courses blocks

In 3.6, categories were never displayed in the Dashboard.

In 3.7, a new parameter was added to the Course overview block to decide whether to display them or not (MDL-64855). This parameter only affects the "Course overview".

But then, the behaviour for the Starred and the Recently accessed courses blocks is not the same:

1. The Starred block never displays the category name.
2. The Recently accessed courses block always displays the category name (it was added in MDL-64376).

This information should be reviewed to make it more consistent.